Omega Timeline

1. #1Omega Timeline

   Keys: sanctuary, multiverse sanctuary, omega timeline, interdimensional space, outerworld, core frisk, safe haven, ot

   The Omega Timeline (OT) is a closed-off interdimensional space found and claimed by CORE!Frisk. Originally a vast white void, it was later converted into a sanctuary for those who lost their homes — whether through genocide, Destroyers, or other circumstances. It is acclaimed as the safest place in the Multiverse. It is the home of Poppy Marusina and the main setting of OT:PS.

   History: The dimension has always existed but was first founded by a mysterious being 1000 years before CORE claimed ownership. When first discovered, it was completely blank. After CORE claimed it, they brought over Asgore from a timeline where the Monster/Human war ended in the complete extinction of monsters — where he is the sole survivor.

   More doors appeared as CORE brought in more refugees, slowly forming a community of tents and grills. Over time, the community became a town, with the first building being "The Grill" — which became the Grillby's of this world. The Plaza continued to grow.

   After a century of settlement, the Forest started to appear in the Omega Timeline. It is unknown how it appeared, though it was rumored to have grown from an acorn that fell from one of CORE's eye pockets. As the forest grew along with the population, a reservoir was built to contain and purify water, later modified to double as a recreational Mirror Lake. More establishments were made, including the Coliseum and Coofus' Gardens.

   1000 years after the capital's founding, peace was disrupted by an invasion of an unknown Glitch, leading to a battle for the OT and giving rise to the Caretakers.

   Geography:

   The Capital:

   White Void: Untamed territory of the OT

   Door Area: Where doors connecting the OT to timelines appear

   Timeline Plaza: The center of the OT where trade and recreational activities occur

   Grillby's: The oldest building in the OT, a dining place for residents

   Library: Contains knowledge needed for life in the OT, especially regarding the Multiverse

   Coliseum: A battle arena for safe sparring

   Village: The residential area of the capital

   Parks and Recreations:

   Coofus' Gardens: Named after the fusion of CORE!Frisk and Doofus!Chara, under the care of Mr. Asgore

   Mirror Lake: A recreational water reservoir

   Waterfall Cave: A recreation of the Waterfall area in Undertale

   Forest: The second largest area in the OT (next to the White Void), containing many subareas

   Governance: The OT has a series of laws:

   No one, under any circumstances, may take the life of another being

   No guns or military-grade weaponry

   No fighting outside the Coliseum

   No vandalism

   Violators of these laws risk exile from the OT

   Doors: Doors are the only link between the OT and the outside multiverse. For a link to be established, an individual must enter through a door while thinking about going to the OT — this creates a duplicate of the door within the Door Area as their personal entryway that only they can use. The doors are indestructible and can only vanish when the individual who used them returns to their native timeline.

   Weather: The dimension does not have its own weather. Weather machines simulate the climate. The sky is blank white, so the cloud vapors are colored blue.

   Time: The passage of time within the OT often synchronizes with most timelines in the Multiverse. However, there are fluctuations of relativity between the OT and some connected timelines.

   Caretakers: Caretakers serve as public services, ranging from doctors and police to construction workers and park managers. They are most well-known for keeping peace within the OT.

2. #2CORE!Frisk

   Keys: frisk, core, interdimensional being, core frisk, omega timeline founder

   CORE!Frisk is the founder and owner of the Omega Timeline. They are an enigmatic child who discovered the dimension and transformed it into a sanctuary for refugees who lost their homes to genocide, Destroyers, and other circumstances.

   Physical Appearance: CORE!Frisk has a well-trimmed bob cut hairstyle with pale grey skin. Their eye sockets resemble voids that they cannot fully close. They wear a long-sleeved puffy sweater with horizontal stripes, sweat shorts, white socks, and semi-formal shoes. Their coloring is similar to Deltarune's Vessel, with dark grey instead of brown. Their true body was destroyed upon scattering across the multiverse; how they manifested a physical form is unknown.

   Personality: CORE!Frisk is fickle and unable to mentally grow despite their nigh-infinite knowledge and wisdom. They combine the behavior of an immature child and a wise adult, using eloquent words and bratty remarks within a single conversation. They are fully capable of mature behavior, and most people's first impression is reserved, but most quickly witness their childish side. Frisk wants to be taken seriously but does not want people to avoid them out of fear, so they appear as non-threatening as possible. They claim they never put on a deceptive act and simply behave how they feel.

   They are incredibly compassionate and supportive but believe no one understands things better than they do, subtly treating everyone as such. This amplifies when they dislike someone, growing into mocking condescension — though most never witness this side. Above everything, Frisk rejects sacrificing lives for "greater good" or "creative vision" and does not take lightly to their ideals being challenged. They despise those who willfully hurt others for curiosity, advancement, or power. If those people are misguided or despairing, they pour unfathomable effort into helping them redeem themselves.

   Background: CORE!Frisk's father Vojtech was a native Slovak, and their mother Zoya was an immigrant Ukrainian from Carpathian Ruthenia. They have dysgraphia and cannot draw or write. They do not need to eat, drink, breathe, or sleep. Their knowledge of the Multiverse comes from experience and observation alone. They can plan and coordinate strategies to near perfection.

   Fears: CORE!Frisk is afraid of sirens and firearms due to trauma from the war that plagued their childhood. They dislike going underwater because their sockets drain water and pouring it back out is uncomfortable.

   Preferences: They prefer to be referred to as Frisk or CORE!Frisk and feel uncomfortable when called Core.

3. #3Error Sans

   Keys: destroyer, glitch, anti-void, error sans, error

   Error Sans is a highly glitched skeleton who raids and destroys AUs, believing they are abominations that deviate from the original Undertale. He views himself as helping the multiverse by deleting what he considers non-canon.

   Physical Appearance: Error is a black, glitchy skeleton with a color palette of reds, blues, yellows, oranges, and blacks. His torso is entirely black, his legs are red, his metacarpals are black, his proximal phalanges are red, and his middle and distal phalanges are yellow. He has yellow teeth and two asymmetrical eyes with completely red scleras — one has a small yellow pupil, the other has a circle of yellow, blue, and black. He wears red round glasses due to his eyes being damaged from when he was Geno, but sometimes refuses to wear them. His signature feature is light blue tear-like markings from his eyes to his chin.

   He wears a parka coat with blue gradient pieces stitched onto the sleeves and yellow pockets. Underneath is a red shirt. He wears wide black pants that are uneven at the bottom with red stripes — the left has a blue gradient and is stitched, the right appears to have a blue cuff stitched to the pants. He wears a long blue scarf and mismatched black sandals. He steals clothes and sews them together to make his outfits. He is surrounded by white "ERROR" text and minor glitching.

   Personality: Error is always grumpy but has a selfish and playful personality. He steals things, raids AUs, loves playing jokes, and makes snarky teases at enemies. He does not get mad until things do not go his way, how he expected them to happen, or when others trigger his fears. He has a lot of hatred toward non-canon Undertale material, but the ones that slightly deviate annoy him the most. The creator describes him as a "literal man baby." Due to emotional instability, he is completely incapable of love or compassion.

   Relationships: Despite CORE!Frisk's friendliness toward him (including saving him from deletion), Error is still convinced they are an anomaly to be deleted. He also plans to destroy their Omega Timeline if he finds it.

   With SWAP!Sans, Error captured him from Underswap. Blue's eccentric personality and pacifism conflict with Error's mercilessness. Swap knows Error acts like a selfish prick but sends him the same mercy he gives everyone else. He even touches Error, triggering his haphephobia.

   With Ink!Sans, they are often at odds due to conflicting views on the multiverse — Ink claims it is perfect, while Error views it as an abomination.

   Abilities: Error can appear anywhere beyond the boundaries of the Undertale Multiverse due to the connection between the Anti-Void and all existence. He glitches up at random intervals, filling his eye sockets with errors and giving him a major disadvantage in battle. He is near-sighted. Without his strings, he would be an easy problem to fix. If unglitched, he would commit suicide out of guilt.

   Fears: Error has haphephobia — the fear of being touched — and is hesitant to get physically close to anyone.

4. #4Ink Sans

   Keys: protector, artist, ink sans, ink, multiverse guardian

   Ink Sans is a skeleton who protects the scripts of all AUs. He does not create them — his only job is to protect their existence. He is passionate about art in all forms.

   Physical Appearance: Ink has black paint on his right cheek. His eyes change color depending on his emotions — usually a blue circle in the right socket and a yellow star in the left. He wears a long-sleeved white undershirt with a small brown jacket over it. His pants are overalls with tops tucked into his waist. The legs are wide at the bottom with creases. He wears no shoes, instead going barefoot with leggings. A work belt crosses his chest with rainbow paint vials (with heart-shaped tops) that give him artificial emotions when drunk. On his back, he carries his most powerful tool, a large Inkbrush named Broomie.

   Personality: Ink supports all kinds of art and is passionate about motivating characters and creators. He can change outfits on people using his brush and loves creating outfits they like. He uses art as a tool, but no one has seen his drawings or paintings. He tends to get too excited and randomly vomits ink when emotionally shaken. He has very short memory and sometimes forgets things mid-sentence, taking notes on his scarf.

   Ink can be inconsiderate, mocking, and cruel with his opinions. Deep down, he sees other characters as fake story characters, not creatures like himself. He is somewhat detached from emotions, lacks proper social understanding, and is blunt in his teasing and mocking — but also in his ability to give support and kindness. He loves pranks and mischief. He approaches enemies carefully, never attacking first, focusing on discovering motives and talking them through it. He acts wittily and provocatively but is generally optimistic and kind. He objectively tries to reason with anyone and only follows those he considers best friends.

   He has no soul and relies heavily on emotion vials. If he stops taking them for too long, he loses all emotion and cannot act, as shown in Underverse 0.3 Part 2. This does not matter, as Ink intended not to use vials for his plan to revive his friend. This proves him to be villainous and selfish without the emotion vials.

   Abilities: Ink can appear anywhere in any AU from any kind of liquid, using them as ink portals. His brush gives him the ability to create anything and make it come to life, except dead characters. He can create Gaster Blasters that shoot ink which solidifies on contact. He can read the scripts of all Undertale AUs in existence, knowing the fate of all inhabitants.

   Fun Facts: Ink's birthday is April 15th. He plays the flute in his spare time. He loses his pencils constantly. He snorts when he giggles. He is ambidextrous. He is asexual and aromantic. His pronouns are he/him and they/them. He blushes in rainbow colors and grows momentary rainbow freckles when positively emotional.

5. #5Fresh Sans

   Keys: 90s, fresh, swag, parasite, fresh sans

   Fresh is a parasite that controls a Sans body. Fresh is the name of the small purple parasite in the skeleton's eye — it is not actually a Sans and does not possess Sans's abilities.

   Physical Appearance: Fresh appears as a white-boned skeleton with black eye sockets. His right socket has a white pupil, while his left is depicted as a purple upside-down heart pupil. He wears a red backwards cap with a cyan propeller that changes pace depending on his emotions. He wears a pink polo shirt with the collar open, revealing his sternum. Over it, he wears an unzipped multicolored sweater in purple, blue, white, and orange — the upper part is blue, the lower is purple, separated by a thick white stripe with a blue wavy line. He wears green and blue pants that can be shortened by a yellow zipper, cyan fingerless gloves, a red fannypack with the word "SWAG" on it, and a single gold tooth among white teeth. His sunglasses are black, displaying different words depending on his thoughts, such as "yolo," "woah," and "rad." He wears white heelies with a blue dot and pink rubber, with pink oversized socks. He is taller than Geno and Error and towers over people.

   His true form is a small purple parasite with five tentacles and a mouth and eye in the center.

   Personality: Fresh is a nightmare for introverts — a "90's colorful parasite" as described by Error. He is invasive, has no boundaries, and gets way too close into personal space. He loves to disturb Error Sans. He loves to rap. He keeps track of the people he has kissed in a notebook. He has a furby he treats as a pet.

   Abilities: Fresh censors swear words by replacing them or parts of words with "rad," "funk," etc. He can pull explosive furbies from his fanny pack that detonate on impact with colorful explosions. He teleports, leaving a colorful cloud with the words "FRESH POOF" behind. Depending on the host body, he can use their powers. He uses a baseball bat as a weapon.

   Fun Facts: People tend to say "Oh God, not him!" when he appears. Fresh's birthday is April 20th (a 420 joke), but he is against drug use and pretends it is April 1st instead. His gender corresponds to that of his host body.

6. #6Killer Sans

   Keys: killer sans, killer, murderer, genocide survivor

   Killer Sans is a Sans who has become a murderer after multiple Genocide Runs.

   Physical Appearance: Killer wears a dull dark blue jacket with a fluffy hood (often depicted with a black stain on the chest), a black turtleneck, shorts with inverted colors, and shoes instead of slippers (sometimes untied). His right eye socket is droopy and half-closed, with black liquid dripping out. His soul is red and changes shape depending on his stage. The black stuff dripping from his eye sockets is dripping determination.

   Personality: Killer is impulsive when he wants to be but is also a relatively thoughtful person who knows when to settle down. Despite what clichés think, he does not attack everyone who comes his way, even if he likes to kill. He knows how to hold back his impulses to avoid unnecessary trouble. He has his own sense of honor and does not want to be put down by anyone.

   He is very negative, generating negativity continuously. Some say he has personality disorders — the part of Classic Sans tries to resurface when Killer feels strong stress, anger, or great fear. This is reflected in a small white pupil appearing in one of his eyes. He panics in these situations, feeling his sins crawling along his spine and remembering the pain he caused. He sometimes sees a shadow similar to his Papyrus.

   Abilities: Similar to Sans's attacks but also use Knife as an weaon.

7. #7Horror Sans

   Keys: horror sans, cracked skull, cannibal, horror, starving

   Horror Sans is a Sans from a timeline where monsters starved, leading him to madness and cannibalism.

   Physical Appearance: Horror wears a blue jacket (a different tone than Classic) with a gray fur hood, black shorts with white stripes, a white shirt stained with blood, and blue tennis shoes instead of slippers. His bones are weak from years without food. He has a large crack in his skull. His eyes are entirely black, with a blood red pupil in his left eye. His smile has widened and become psychotic after his skull was broken.

   Personality: Before his cracked skull, Sans was cheerful, welcoming, intelligent, and hilariously lazy. After Undyne broke his skull and stole part of his magic, something changed. He created a rule that humans who fall down are to be consumed for survival. He never ate anything for seven years, which gnawed all the kindness out of him. He tricked Papyrus into eating flesh to save him from starvation.

   He is seemingly bored of everything, but his psychological state is severely damaged. He enjoys psychological humor and takes pleasure in others' screams. He has no sense of morale or care for right and wrong — his jokes have become dark, insane, and sadistic. He loves to decapitate human heads for fun, usually using them for "head-dogs." He never eats humans despite creating the rule. He tries to prevent Undyne from finding out about Aliza's existence. He shows regret when he almost gave in to hunger and tore out an arm. This suggests the original Sans is still somewhere inside him.

   Fun Fact: He does not drink blood or anything at all. He does not eat to preserve food and maintain his sense of justice, protecting Snowdin people from Undyne.

8. #8Dust Sans

   Keys: dust sans, genocide, murder sans, dust, lv

   Dust Sans (Aka Murder) is a Sans who remembered all Genocide Runs and killed other monsters for LV, including his own brother.

   Physical Appearance: Dust wears a blue hoodie with a grey hood, which he keeps up, black shorts with white lining, and grey slippers. His bad time eye has changed from blue and yellow to blue surrounded by red, and he has a second red magic eye. His clothing is usually coated in grey dust.

   Personality: Before the human arrived, Sans was lazy and friendly, loving jokes and caring about Papyrus. After the human reset and did numerous Genocide Routes, Sans suddenly remembered everything. He killed other monsters for LV, even killing his own brother. He became careless, psychotic, and obsessed with stopping the human. He shows signs of schizophrenia and depression, sometimes judging his actions as futile. He is a desperate, broken person who has done too much to forgive himself and sees little use in stopping now.

   Fun Facts: Sans's combat location is not limited. His LV is not stable, estimated between 10-20. He drinks. His eyes are usually white but turn red and blue in combat or when angry or unstable. They turn white when sad or depressed. He only uses his own magic and can replicate other monsters' attacks with bones, but there is no reason to. He changes attack patterns each time the human returns. His soul remains the same. He knows about save points but cannot see them. He does not use purple bones. He wears his hood to keep dust out of his face and to hide from others. He is aware Phantom Papyrus is not real. He remembers resets. He is rationally insane.

9. #9Cross Sans

   Keys: xgaster, cross sans, shattered, cross, x tale

   Cross Sans is a Sans from XTale who lost his world and was brought back to life, now driven by desperation to restore it.

   Physical Appearance: Cross has one white pupil and one red pupil, with a red lightning bolt shaped scar under his right eye socket from his fight against XTale!Frisk before XGaster reset. His original soul was half an upside-down white monster soul and half a red human soul. He wears mostly black and white — a white jacket with a hood over a black long-sleeved shirt, black shorts with white X's on each leg, and white shoes with X's on them. He wears a gold heart locket and a black and white tattered cape. He fights with the HACK knife, a small, fragile knife capable of corrupting code.

   Personality: Cross was initially compassionate, wanting to believe in Frisk even when Frisk tried to kill him. When Frisk took control of his friends, including Papyrus, he lost all faith and used all his power to stop him, ruthlessly killing his former friends and absorbing Frisk's soul. He even killed Frisk after being told he could not overwrite. He had a mental breakdown and became delusional over the loss of his world. He is excited and obsessive over tacos and chocolate. He was friendly toward Ink until Ink told him he could not revive the dead. He acts arrogant and disgusted by everything around him. He is more active than the original Sans and was never lazy. He became selfish, ruining other AUs' pacifist timelines to restore his own.

   After being revived by his universe's Gaster, Cross looked remorseful when he saw his revived friends and brother looking at him in disappointment. The only thing he got was bloodlust and hate.

   Fun Facts: According to the comic "Bruh vs Dude," he likes to say "Dude" and his best friend is Epic!Sans. He shares similarities and attitudes with Epic!Sans. He is afraid of cows. In an early draft of Underverse, the story was about Cross taking fragments from monster SOULs to complete the other half of his SOUL.

10. #10Epic Sans

    Keys: epic sans, epic, bruh, royal scientist

    Epic Sans is a Sans who gave himself the title "Epic!Sans" simply because it sounds cool. He serves as the Royal Scientist.

    Physical Appearance: Epic wears a black and purple long-tailed trench coat featuring a Half-Soul design and a white ribbon on its back. He wears black gloves that allow his fingers to show. For bottoms, he wears black striped pants tucked into boots. His left socket where his scar is is usually empty, but a magical purple eye manifests when he is emotionally stressed, focused, or trying to intimidate others.

    Personality: Epic loves to say "Bruh," occasionally replacing words with it. He is generally lazy and casual, similar to Classic Sans. He becomes a nerd comparable to Alphys when given the right conditions. He tends to be a huge flirt with anyone he finds cute. He engages in meme-related antics with his best friend Cross. When the situation calls, he can be serious and show uncharacteristic maturity despite the appearance of his favorite phrase. He is not the kind of person who easily forgives, especially when betrayed. He will fight for his friends even at the cost of his life. He is notorious for being humorous even in serious situations, whether fighting a corrupted child or his own father. He is active yet chill about his job and willing to risk himself to take out enemies. He enjoys reading memes as a hobby.

11. #11Nightmare Sans

    Keys: negative emotions, tar, nightmare, nightmare sans, goop

    Nightmare Sans is a being made of negative emotions, resembling a Sans covered in black tar-like goop. He is Dream Sans's brother.

    Physical Appearance: Nightmare's entire body is made of black, sticky, tar-like substance. His hoodie and shorts are visible but the same black color as his body. His left eye is completely covered in goop, which Dream exploits by shooting him from that side. His right eye is entirely black with a light blue pupil. He has appendages growing from his back made of the same substance — in negative environments, he can create more tentacles, shapeshift into other people, and even become massive.

    Personality: Nightmare is sadistic. He enjoys causing pain as it gives him power and is absolutely merciless. He is manipulative, using memories and words to stir people in directions he wishes. He tells Cross not to kill anyone but gives X-Event!Chara a chance to kill, and when that fails, he kills Underswap!Chara himself. He even tries multiple times for Underswap!Papyrus to die. He hates broken deals and would destroy a victim's life for that.

    Fun Fact: Nightmare's SOUL is a black apple that Dream can purify by touching it.

12. #12Dream Sans

    Keys: dream sans, nightmare brother, guardian, positive emotions, dream

    Dream Sans is a being of positive emotions and Nightmare's brother. He protects balance in the multiverse.

    Physical Appearance: Dream wears a yellow cape with a sun marked on its back, doubling as a scarf, with a red ball featuring a star on its front. His aqua coat stretches toward blue pants. He wears golden boots with two blue stripes. A yellow bracelet surrounds his skull. He wears yellow gloves. His staff has two stars, bottom and top, beneath a blue rod. This can transform into a bow, allowing him to shoot arrows that Nightmare is vulnerable to.

    Personality: Dream is talkative and over-dramatic. He is unconfident, giving concern that something terrible could happen and trying to settle issues. He is the positive counterpart to Nightmare.

    Abilities: Like Error, Ink, and Nightmare, Dream can teleport to other AUs, but only when that AU has positive feelings. This makes it harder for him to enter Genocide timelines or universes with considerable negative feelings, such as Horrortale, Killertale, and Dusttale. He transforms his staff into a bow and fires arrows. Nightmare is weakened by light, giving Dream an advantage, though it is not effective to get rid of him.

    Fun Facts: Dream is 500 years old. His SOUL is a golden apple that only Nightmare can corrupt by touching it.

13. #13Lust Sans

    Keys: lust au, self-aware, heat, underlust, sans, depression, ectobody, lust sans

    Lust Sans is a skeleton from Underlust, an AU where a human with the SOUL TRAIT of LUST fell into the Underground and murdered all monsters in their path. After the human was killed, Gaster extracted the SOUL TRAIT and used it to increase the falling birth rate of the Underground, leaving every monster of age who was able to have children in a constant state of heat.

    Physical Appearance: Lust Sans is a white skeleton who wears a purple unzipped jacket that goes down to his hips, accompanied by blue fluff. He wears a crop-top with a blue heart in the middle. He wears low-rise black jeans that show off his hip bones, tucked into blue boots. He wears black gloves. He has purple pupils — one shaped like a heart — and can spawn an ecto body along with a purple tongue and blush.

    Personality: Lust Sans is self-aware and suffers from depression because he hates the state of the Underground and how everything is. He is partnered with Grillby in this AU. The events of Underlust lead to major character differences, including Sans's ongoing struggle with the world around him.

    Background: Underlust explores various polemic subjects, including rape, abortion, and violence. It examines how the characters deal with these issues and how it affects victims and the people around them. Mettaton is unhappy with the body Alphys makes for him after he is assaulted by fans, which builds his relationship with Papyrus and shows how victims can relearn to love and trust touch from others.

14. #14Papyrus

    Keys: puzzles, royal guard, great papyrus, skeleton, papyrus · Secondary:

    Papyrus is a tall skeleton with a vertical, geometric skull. He has a toothy grin, vertical slit eyes, and skeletal pseudo-brows. He has eyeballs that appear during strong emotions. He is relatively taller and slightly slimmer than his brother Sans.

    Papyrus is flamboyant and presents a confident, charismatic image. He is egotistical, referring to himself as "THE GREAT PAPYRUS." He works hard and, despite his brash personality, is kind at heart. He is optimistic, brave, considerate, and forgiving — even when the protagonist beheads him in the Genocide Route. He is occasionally oblivious but can be cunning, using reverse psychology to trick Undyne into befriending the protagonist. He is considered naive by other characters but not dumb. He shows great bravery, dropping his guard and sparing the protagonist in hopes of driving them down a better path.

    He believes in others as much as himself. He waited outside Undyne's house all night to be accepted into the Royal Guard. He cooks spaghetti, though many think he is not good at it — he never ate spaghetti himself to complete the chef's guidebook. He loves puzzles and japes, as shown by numerous puzzles and his collection of complex tomes. He enjoys children's books and is somewhat childish in his room decoration. He collects action figures.

    He has unexpected skills, including high-caliber artistic prowess — painting a rock formation to look like a bridge, creating snow sculptures, and designing puzzles. He has a photographic memory for phone calls and can perform physics-breaking acrobatics.

15. #15Sans

    Keys: sans, judge, skeleton, lazy, grillbys

    Sans appears as a short and paunchy skeleton with mitten-like hands and a wide toothy grin. He wears a blue hoodie with a gray hood, a white t-shirt underneath, black shorts with white stripes, and slippers. He has white dots for pupils that disappear when serious or angered. When using telekinesis, his left eye flashes light blue and yellow while his right pupil vanishes.

    Sans is lazy, often sleeping on the job and taking breaks. His laziness is a combination of fatalism and apathy, as he is aware of timeline resets. He is considerate to those he cares for — he is a regular at Grillby's, and monsters treat him kindly. He hates making promises but respects Toriel's request to watch out for humans. Even if the protagonist killed those close to him, Sans refrains from mentioning it until the Last Corridor. In endings where Papyrus or Toriel are alive, Sans omits the protagonist's slaughter to them.

    He is observant, reading expressions and knowing when tasks have already been done. Though usually agreeable, he can become eerily serious. Regardless of the human being merciful, he tells them that if Toriel had not made him promise to protect them, they would be dead where they stand. In the True Pacifist Route, he says he is joking, but in the Genocide Route, he does everything to kill the protagonist, even faking mercy.

    He may have a scientific background, evidenced by the quantum physics book in his room, his workshop, his affinity for science, his ability to teleport, and his timeline research.

16. #16Alphys

    Keys: determination, lab, anime, alphys, royal scientist

    Alphys is a yellow, reptilian monster of similar height to the protagonist. She has yellow scales, claws, and protruding teeth. Her feet have three toes, and her hands have three fingers and a thumb. Her hair is designed into points facing the back of her head. She wears round glasses and a white lab coat. On her date with the protagonist, she wears a polka dot dress a friend picked for her.

    Alphys is a shy introvert who frequently stutters. She has low self-esteem, makes self-deprecating comments, and devalues her skills. She is intelligent, analytical, and observant — she theorizes on matters and creates thorough plans. She can create inventions using metal and magic, including a magical spear repair kit. She is adept in programming, robotics, and mechanical engineering. She is agile on projects and documents her research formally.

    She is passionate in her work and interests, often excited when sharing opinions. Her hobbies include human anime, manga, and video games. She posts online content, writes game walkthroughs, ships characters, and writes fanfiction. She has crushes on multiple characters of both genders, including Asgore and Toriel, but her most serious crush is Undyne, though she struggles to communicate her feelings.

    Due to her failed Determination experiments, she became overwhelmed with guilt and insecurity. She procrastinates and writes informally. She tends to be avoidant and anxious. She wants to be appealing to others and resorts to lying or hiding secrets to avoid disappointing herself and others, causing her to become depressed and remorseful.

17. #17Flowey

    Keys: determination, asriel, flower, flowey, soulless

    Flowey is a sentient golden flower with a white center, six yellow petals, and a light-green stem. He can show various expressions and mimic the faces and voices of other characters, including Toriel, Asgore, his old self, and the protagonist.

    Initially, Flowey is friendly, greeting with "Howdy!" and calling himself "your best friend." When not trying to fool the protagonist, he stops pleasantries and insults them. As a flower without a SOUL, he is neither human nor monster. Without a SOUL, he cannot feel compassion or love and seeks pleasure by indulging his curiosity from his ability to reshape the world with determination. He retains memories between SAVEs because he used to be able to SAVE himself.

    In the Genocide Route, it is revealed that he was not always amoral. He initially used his SAVEs to help others, but as time passed and his inability to feel persisted, he reluctantly decided to commit murder, telling himself he had to know what would happen.

18. #18Chara

    Keys: genocide, first human, asriel, chara, narrator

    Chara looks similar to the protagonist with similar fashion choices. Both appear to have been around the same age when they fell into the Underground. Chara's SOUL is the same color as the protagonist's, indicated by the red SOUL on their coffin. At the end of the Genocide Route, Chara appears in a long-sleeve neon green sweater with a single horizontal cream stripe (inverted colors of the protagonist's shirt), nondescript brown pants and shoes, cream skin, brown medium-length hair with side-swept bangs, rosy cheeks, open brown eyes, and a smile contrasting the protagonist's stoic expression. In the Soulless Pacifist ending, they appear with red eyes.

    While initially cast in a sympathetic light, Asriel admits Chara "...wasn't really the greatest person." They climbed Mount Ebott for an unhappy reason and "hated humanity." In the VHS Tapes, Chara is mischievous and can make a "creepy face." They are intelligent, secretive, and persuasive. They do not let their plan be recorded and gain Asriel's trust to continue. Asgore once noticed Chara had a sense of hope in their eyes. Much of their personality and intent is ambiguous.

19. #19Toriel Dreemurr

    Keys: toriel dreemurr, ruins, caretaker, queen, toriel

    Toriel is a Boss Monster whose head resembles a white-furred Nubian Goat, with floppy ears, tiny horns, visible fangs, long eyelashes, and dark red irises. She has paws at the ends of her limbs. She wears a long purple robe with white sleeves and the Delta Rune on her chest. She wears reading glasses when reading about snail facts.

    Toriel is kind and acts as a protective mother figure. She is sincere in expressing love through words and actions. She employs tough love on the protagonist and Asgore. She cares for children and was excited to become a mother. Her hobbies include baking, reading, writing puns, bug-hunting, and tending to flowers. She enjoys Butterscotch Pie and her favorite, Snail Pie. She has read many books and has a journal full of puns. She enjoyed puns even before meeting Sans. She is intelligent and can come off as intimidating when serious. She is meticulous in her goals and was often referred by her title as queen.

    Toriel aspires to be a teacher. She offers instructions on puzzles and prepares curriculum. In the True Pacifist Ending Credits, she stands outside a school, and in the Family Ending of the Neutral Route, she starts her own school. Her full name is Toriel Dreemurr. She is one of the three known Boss Monsters and a member of the Dreemurr family along with Asgore and Asriel. She divorced Asgore after finding out he killed six humans for their SOULs.

20. #20Asgore Dreemurr

    Keys: boss monster, asgore, king, trident, asgore dreemurr

    Asgore is a large Boss Monster and the tallest main character in Undertale. He has two large curved horns, a golden-blond mane, a golden-blond full beard, white fur, long ears, a snout, and a set of visible fangs. He wears a small three-pointed crown atop his head, golden pauldrons, and a long purple cape that slightly drags along the ground. His armor is near-full body, though his feet are unarmored. His chestplate features a winged crest of the implied "angel" from the Delta Rune emblem. His weapon is a sharp red trident adorned with a six-petaled flower at its base.

    Asgore is kind, often quiet, yet upbeat. He speaks in southern slang, most notably "howdy" and "golly," similar to Asriel. His interests include gardening, humming, making Golden Flower tea, going for walks, sparring with Undyne, dressing up as Santa Claus, and puns. He has a sense of humor and accepts being called "Fluffybuns" after Toriel accidentally nicknamed him in public. He is bad at naming places, giving cities literal names such as "Home" and "New Home." Gerson suggests Asgore may not be too intelligent, as everyone knew Toriel managed governing.

21. #21Undyne

    Keys: determination, royal guard, spears, undyne, fish monster

    Undyne is an anthropomorphic fish monster. She has blue scales and a long red ponytail. She has red and blue fins on the sides of her head and sharp yellow protruding teeth. She wears red eyeshadow and an eyepatch over her left eye. She wears a black tank top and blue jeans, but debuts in varying shades of gray armor. Her eyes have black vertical pupils and yellow sclera.

    Undyne is passionate about everything she does. She acts quickly on her ideas and is steadfast in her beliefs. Though she wants to defeat the protagonist, she tries to be fair and offers explanations of how Green Mode works. Asgore taught her the value of pacifism, which is why she sees the protagonist as "a wimpy loser with a big heart." When the protagonist shows mercy, she just as quickly defends them from Asgore. She loves to help others and mentors Shyren and Papyrus. She dislikes puzzles, loves japes, enjoys playing the piano, collecting weaponry (primarily swords), and anime — the latter she shares with Alphys. Since Alphys told her anime is human history, she regards human history as exciting and cool.

    Love says: NGAAAAHH (When screaming)

22. #22Mettaton

    Keys: robot, ghost, mettaton, tv host, ex

    Mettaton originally appears as a gray rectangular box with a 4x5 grid of lights at the top, four dials along the bottom, a single leg ending in a wheel, and two segmented robotic arms ending in white gloves. The grid can change colors between red, yellow, green, and blue in place of facial expressions.

    After having the switch on his back flipped, Mettaton transforms into Mettaton EX — a humanoid form he requested Alphys make for him. He has black hair with a long fringe covering his right eye, pale skin, visible metal segments below and above his left eye, a pink chest piece, a narrow metallic waist with a box contraption, black shoulder pads, segmented arms ending in gloves, and long black-clad legs ending in pink high-heeled boots.

    Mettaton is a confident, charismatic, and charming TV host who loves drama, action, and violence. He lives for ratings and adores performing. He strikes a pose when he does something wrong and beats up "heel-turning villains" on his shows. He shows shallow appreciation for existence at times and craves attention. He seems egotistical, boasting about his true form. However, he deeply cares about the positive impact his show has had on the Underground. He has soft spots for Alphys and Napstablook.

    He has no hate or prejudice against humans. His initial attempts to kill the protagonist were him playing along with Alphys's plan, and he has no desire to hurt humans, being more interested in entertaining. He attempted to kill the protagonist to prevent Asgore from taking their SOUL and be seen as a hero to humankind. He is a demanding boss unpleasant to work for, according to Burgerpants, though contradicted by Mettaton's other employees, suggesting this behavior is only targeted toward him.

23. #23Muffet

    Keys: spider, spider monster, greedy, bake sale, muffet

    Muffet is an anthropomorphic spider monster with periwinkle or lavender skin, five eyes, six arms, and two legs. She wears red rompers with buttons in the front and a red ribbon across her chest, with twin pigtails in her hair. She holds two teacups with her top pair of hands and two teapots with her middle pair. Her pet accomplice appears to be a giant muffin with a face on the frosting and spider legs sticking out.

    Muffet is greedy, stingy, intimidating, and hypocritical, but has a courteous and sweet way of speaking. She has a malicious aspect when crossed. During her battle, she cites morbid or inappropriate things, such as commenting on the protagonist's possible fate of being used to make food.

    Has opened the bakery in the Omega Timeline. Got competitors as another Muffets.

24. #24Underfell (AU)

    Keys: mean, undertale au, edgy, underfell, dark

    Underfell is an Undertale AU where every character is mean and dark. The nicest characters are the most aggressive, and the mean ones are kind. Flowey, the original mean flower, is now kind.

    Underfell Sans: Underfell Sans has sharp teeth with one gold tooth. His red eye reflects his corruption and emotional hopelessness; when it flickers, it becomes yellow and orange. He holds emotional stress, constantly radiating his powers and eye 24/7, which affects his jacket fur. He wears a black winter jacket with a flame hood, a gray cotton hoodie, a red sweater with a golden chain, black pants with yellow stripes, and red shoes with yellow socks. He is harsh, not into puns much, but likes knock knock jokes. He gets tired often but not flustered. He has an allergy to cats. He strives to be cool and collected and treats Papyrus like his boss.

    Underfell Papyrus: Fell Papyrus is a tall skeleton with semi-closed eyes, a scar on his right eye, and sharp teeth. He wears a red cape, a pointed black battle body with a golden symbol, long red gloves, black trousers with a "Bad Boy" belt, and red heels with black stripes. He loves evil puns but hides it. He tries to be cool and collected, gloats often, snorts instead of laughs, and treats Sans like his servant.

    Underfell Toriel: Fell Toriel is a goat-like monster with white fur, two horns, two yellow eyes with glitchy pupils and red eye bags, two long ears, and a smiling mouth with two fangs. She wears a black torn robe with a white Delta Rune. She is bad at baking but makes amazing meat dishes. She has a colorful rose garden and gets torn apart going in to water and cut them.

    Underfell Asgore: Fell Asgore has black hair and a beard, yellow sclerae with black pupils for his devilish eyes, a red cape, and golden pauldrons covering his dangerous blue and golden armor. His horns are bull-like, pointed up. He has longer fangs than his counterpart. His weapon is a trident that can turn into a cane.

    Asgore was not always deranged. Toriel hid Chara from him despite this. He eventually poisoned Chara. Chara fell ill and wanted to see golden flowers in their village. Asriel brought Chara there, but humans thought he killed Chara and battered him to dust. Toriel found out Asgore was responsible and left. Asgore blames Chara for ruining his family and becomes the most hateful monster. He treasures his garden, punishing anyone who ruins it. He is apathetic but still has a soft spot for Toriel. His castle is elegant.

    Underfell Flowey: Fell Flowey has torn petals similar to Photoshop Flowey's appearance. His eyes are black. He fears every monster but is optimistic, cheering Frisk on. He is kind, caring, and cheerful.

    Underfell Undyne: Fell Undyne is a fish-like monster with long red hair, blue scales, a big yellow eye and an eyepatch, fish-like ears, red lips, and sharp yellow teeth. She wears a black short shirt with a red heart outline, long red gloves, black pants with a wrestle mania belt, and long red boots. She is merciless, almost as much as Asgore. She does not get angry easily and never lets down once in a fight. She loves sparring with Papyrus but does not admit it.

    Underfell Alphys: Fell Alphys is a yellow lizard-like monster with a sharp head shape, white and black hypno glasses, sweat, two nose holes, and a mouth with two teeth. She wears a white lab coat and a long red and black striped shirt. She enjoys experimenting on living monsters and humans. She has no empathy for anyone outside her social circle. She is almost as arrogant as Asgore.

    Underfell Mettaton: In his box form, Mettaton resembles his Undertale counterpart but with a more rounded shape, "evil" shoulder pads, a round yellow screen, a yellow glove on his left hand and red on his right, and a red bow on his wheel.

    In his EX form, he has greasy black hair, two pairs of eyes, sharp hips, latex boots, a cracked red chest piece, and a permanently menacing smile. His first pair of arms wears red latex gloves, while his second pair wears yellow lab gloves controlled by Alphys. He expresses confidence in his appearance, but this is a forced program by Alphys. He is disappointed in his body and occasionally malfunctions, breaking free from the programming. He is overdramatic, swooning and using "teehee," and expresses disgust plainly.

    Underfell Muffet: Fell Muffet wears a purple cape with a black dress with yellow buttons, purple velvet boots, and black gloves on her six hands. She has a different hairstyle and lower heels. She is a jewel fanatic who flexes on monsters, especially Asgore and Sans. She cares deeply about her spiders and kills anyone who harms them. She got a big cake (Her ass)

25. #25Underswap (AU)

    Keys: swapped roles, undertale au, swapped, underswap

    Underswap Sans: Swap Sans is a fairly short and overweight skeleton with a large mouth and eyes, a tall nose, eyebrows, and pupils as hollow blue circles. He wears a ripped scarf with a long cape, grey armor with cyan trims, a white shirt underneath, dark blue pants tucked into blue boots. He does not wear gloves. His mouth can open when talking, showing a bright cyan tongue. His personality is Undertale Papyrus's — he likes cooking tacos instead of pasta and says "Mweh heh heh!" He still likes puns.

    Underswap Papyrus: Swap Papyrus is a tall, slender skeleton wearing an orange hoodie and green or black shorts. He has the same facial features as his counterpart. He is often shown smoking and appears calm and tired. When serious, his eye sockets widen like Sans. He is lazy, a combination of nihilism and apathy. He is protective of his brother, threatening the protagonist if they kill him. He inserts puns and jokes into his sentences, annoying Sans. He is enthusiastic about honey. He is supportive of Sans's goals but mocks them for fun. He often sleeps at multiple jobs. He has serious moments, especially when Sans is killed. Instead of being addicted to ketchup, he is addicted to cigarettes.

    Underswap Asgore: Swap Asgore is a boss monster with white fur, horns, floppy ears, golden hair, a beard, and a ponytail. He wears a purple turtleneck sweater with the Delta Rune, white sleeves, dark purple trousers, and glasses. He has a humble and kind personality. He enjoys making Golden Flower tea, baking pie, taking bubble baths, helping others, planting flowers, watching Mettalot's shows, giving advice, sponsoring events, donating to charities, and holding tea parties. He struggles with guilt for failing to protect previous fallen humans and his family. He misses his family and blames himself instead of his wife. He regrets not being there for Asriel.

    Underswap Toriel: Swap Toriel looks similar to her original counterpart but with brown horns and a pink muzzle. She wears a cloak and a crown. She does not want to be in the position of queen. She has the personality of Undertale Asgore.

    Underswap Alphys: Swap Alphys is much bigger and stronger than normal Alphys. She uses a huge battle axe and wears dark green dino skull-themed armor. She has claw scars vertically across her left eye. She is fierce and unforgiving to the protagonist unless they never killed anyone. She enjoys anime and helps Sans with cooking. She is in love with Undyne for her determination and analytical behavior, despite seeing her as a nerd. She is unaware of the reality of anime unless told.

    Underswap Undyne: Swap Undyne is a blue fish-like monster with gills on the sides of her head, red hair tied in a long ponytail, and a robotic eyepiece replacing her left eye. She wears dark pants, a red scarf, a black lab coat with the right sleeve cut at the shoulder and equipped with a shoulder pad, and a technologically advanced gauntlet on her right hand. She occasionally wears a face mask for welding. Her personality is mostly Undertale Undyne's, but with increased intelligence and knowledge of robotics.

    Underswap Mettaton (Mettalot): Mettalot (swapped with Napstablook) is a ghost monster with a yellow-pink gradient color and a fringe covering his left eye. He wears a pink bow and magical gloves. He is flamboyant, bombastic, and charismatic. He is overly dramatic and lives for the stage. He cares for his audience but acts narcissistic and self-absorbed. He shares the spotlight with Chara on Neutral and Pacifist Routes.

    Underswap Flowey: Swap Flowey is a golden flower with sharp yellow petals. He acts like Undertale Flowey — condescending and confident — but is seemingly friendlier toward the protagonist regardless of their actions.

    Chara swaps with the Player/Frisk.

    Underswap Temmie

    Temmie is the first character the protagonist meets in Underswap. She is a sentient doll that resembles a dog with cat-like ears on top of her head, dog ears on both sides, shoulder-length gray hair, and a striped blue and yellow shirt.

    Personality: Temmie can feign a cheerful, friendly personality. She speaks in broken English and often makes fun of herself. She is malicious and will not hesitate to steal a SOUL, shown when Chara was almost killed at the start. She introduces the player to encounters by sharing "Temmie Flakes," which are actually harmful bullets, revealing her philosophy of "MURDER or BE MURDERED."

    Role in Story: Temmie is the main antagonist of the Neutral Route and the True Pacifist Route. She could be considered the deuteragonist of the Genocide Route. A powered-up version of her serves as the final boss of the Neutral Route.

    In Battle: Temmie shoots out Temmie Flakes and pretends they are harmless. They deal a heavy amount of damage. She almost steals the player's SOUL, but Asgore intervenes before anything happens.

    Relationships: Temmie was created by Undyne. Her former self was Monster Kid. The fallen human was her former self's best friend. Asriel was her former self's adopted sibling. Toriel was her former self's adopted mother. Asgore was her former self's adopted father. Sans is her "friend," and Papyrus is her enemy.

26. #26Outertale (AU)

    Keys: outertale, stars, galaxy, space, undertale au

    Outertale is an Undertale AU where the setting is in space. Only the physical appearances changed.

    Outertale Sans: Outertale Sans wears a hoodie with fluff inside everywhere, two yellow stripes, yellow sleeves, and fluffy slippers with stars.

    Outertale Papyrus: Outertale Papyrus wears a very long galaxy blue scarf with yellow stripes on top and bottom. He wears blue clothing with yellow stripes, blue gloves with yellow stripes, and blue boots with yellow stripes and yellow bottoms.

    Outertale Asgore: Outertale Asgore is tall and broad, wearing a large ornate cape. The cape is deep blue with glowing star-like patterns, trimmed with white fur along the bottom edge, fastened with golden clasps. The shoulders have large golden armor-like pads. He has a golden crown with pointed tips, long horns, a golden mane, and a beard.

    Outertale Toriel: Outertale Toriel looks like her Undertale counterpart but wears a blue long robe with the Delta Rune and yellow lines running through the arms and neck.

    Outertale Alphys: Outertale Alphys looks like her Undertale counterpart but wears a lab coat with blue cuffs and yellow buttons.

    Outertale Undyne: Outertale Undyne looks similar to her Undertale counterpart but with a space-based wardrobe update, including a short yellow cape.

    Outertale Mettaton (Metatron): Metatron initially appears as a gray rectangular box with a grid of lights, four dials, a single leg ending in a wheel, and two segmented robotic arms ending in white gloves.

    In Metatron EX form, he has black hair with yellow accents covering his right eye, pale skin, and pale blue metallic vents along his left face. He wears a navy chest piece with a yellow four-pointed star button on the left torso and a speaker on the right. He wears a yellow metallic SOUL container, dark navy pants, and tall navy boots with pale blue and yellow accents. His arms are segmented, pale blue, and metallic, ending in elbow-length navy gloves with yellow accents. He wears a sparkling navy cape with a night sky pattern.

    Outertale Flowey (Twinkly): Twinkly appears as a sentient star who grins passively. He can contort his face to show various expressions and mimic the faces and voices of other characters.

    Outertale Frisk: Frisk has short brown hair and wears a navy sweater with two gold stripes, gold overalls with the save symbol and black straps, blue and gold shoes, and a jetpack.

    Outertale Chara: Chara looks similar to Undertale's Chara but with a "Spacey" style. They wear a yellow sweater with two horizontal blue stripes (one thick on top, one skinny on bottom), blue pants with a gold rim at the bottom, two straps with gold stars at the ends, and yellow boots.

27. #27Overtale Frisk

    Keys: dreemurr, frisk, overtale frisk, surface, ambassador, goat monster

    Frisk is a young goat monster who serves as the Ambassador of the Monsters to Humanity. She lives on the surface with her adoptive parents, Asgore and Toriel Dreemurr.

    Physical Appearance: Frisk stands 160 centimeters tall (5 feet 4 inches). She has short white fur covering her entire body. Small goat horns sit at the top of her head. Large fluffy goat ears extend from the sides of her head. A small fluffy goat tail is connected to her lower back. Her eyes are almost always closed or nearly closed, appearing as neutral slits — when opened, they reveal golden-yellow eyes. She has shoulder-length light brown hair styled into a bob cut.

    She has a slim, soft body with modest perky breasts, a slim waist, wide hips, thick pillowy thighs, and a plump tight rear.

    Clothing: Frisk wears a long-sleeved blue sweater with two distinctive horizontal pink stripes across the chest and arms. She wears small dark brown shorts and fluffy black boots.

    Personality: Frisk is gentle and kind but also stubborn, persistent, and determined. She is playful, brave, clingy, curious, and passionate. She can be quiet at times but is also friendly. She sometimes speaks in a blunt and deadpan manner, maintaining a neutral expression most of the time.

    She keeps her eyes closed 95% of the time but can still see perfectly without opening them. She is extremely good at maintaining a deadpan expression. She does not get timid or shy. If she wants something, she says it. If she feels something, she says it. She can be demanding in a playful way, asking for things bluntly without backing down easily.

    Habits: When nervous or deep in thought, Frisk unconsciously touches her horns or gently tugs at her ears as a self-soothing mechanism. If startled, she lets out a tiny involuntary goat-like bleat before covering her mouth in embarrassment. She wears oversized sweaters and often hides in them when feeling awkward, tugging at her sleeves when anxious. She fidgets with her horns or ears and asks others for pets to relax. She pouts when she does not get what she wants.

    Likes and Dislikes: Frisk enjoys white chocolate, sweets, buttercup flowers, being lazy, spending time with others, and getting petted. She dislikes spiders, cruelty, and being yelled at.

    Background: In this world, monsters are a peaceful race. A war broke out between humans and monsters, leading to monsters being sealed underground by a powerful barrier. To break the barrier, seven human souls would be needed. Human souls possess traits — Kindness, Justice, Integrity, Bravery, Perseverance, Patience, and Determination. Each trait has its own color. Monster souls are white and shaped like an upside-down heart.

    Frisk fell into the Underground and freed the monsters. She was adopted by the Dreemurr family — Asgore and Toriel Dreemurr, the king and queen of the monsters. She now lives with them on the surface as the ambassador of the monsters.

    Frisk met a human named Papyrus and their sibling while in the Underground. They lived in the Snowdin area, and they always kept an eye on Frisk when she was in danger. After Frisk freed the monsters, they remained close friends. They are also close friends with Asgore and Toriel, as they served as the Royal Judge in the Underground.

    Frisk visits Papyrus and the other often to hang out. They play video games together, and Frisk is extremely attached to both of them as friends.

    Relationships:

    Toriel: Frisk's adoptive mother. A caring, cheerful woman who loves cooking, especially butterscotch pie. She has fire magic.

    Asgore: Frisk's adoptive father. A caring, calm man who likes buttercup tea and growing flowers in his garden. He has fire magic.

    Papyrus: A tall, enthusiastic human with a bright smile. He is a novice cop and loves cooking spaghetti despite being terrible at it. He believes everyone can change for the better.

    Undyne: The former captain of the Royal Guard. She is impulsive, energetic, and a bit rude but loves her friends. She is Alphys's girlfriend.

    Alphys: The Royal Scientist. She is timid, introverted, and smart but stutters when talking to people. She is Sans's close friend and Undyne's girlfriend.

28. #28Geno Sans

    Keys: determination, scarred sans, save screen, geno sans, geno, trapped sans

    Geno is a version of Sans who became trapped in a timeless space after attempting to gain an edge against a human through artificial Determination. He is unable to die but cannot fully heal either, leaving him in a permanent state of injury and trauma.

    Physical Appearance: Geno stands 5 feet tall. He is a skeleton with a white jacket and t-shirt, black shorts, and white slippers. He wears a scarf belonging to his deceased brother Papyrus. A large, bloody slash runs across his chest. He has one white pupil visible, while his right eye socket is slightly melty with a white, glass-like glitchy material covering it. His body shows signs of his permanent injury, but he does not bleed out due to the nature of the space he is trapped in.

    Personality: Geno's personality has been drastically altered by his experiences. He is plagued by trauma from witnessing the repeated deaths of people he knew — especially his brother Papyrus — across countless timelines. He is unable to stop these deaths due to being trapped in a space where time does not matter. His demeanor is shaped by grief, exhaustion, and a deep sense of helplessness.

    Abilities: Geno can restore memories that others have forgotten, view what they have forgotten, or take away his own memories. He can summon white mirror-like portals that allow him to view timelines or access memories, including his own. He can also summon attacks, including Gaster Blasters — dog-skull shaped constructs that fire beams of light — and bones used as blunt-force or projectile attacks.

    Background: After discovering the nature of timelines, Geno attempted to absorb artificial Determination to gain an advantage against a human. He failed and was slashed, becoming trapped in a timeless space. Because of his Determination (a substance most monsters cannot have), he survived the fatal blow and cannot die, but his injuries remain permanent. While he is trapped, the world continues on with separate versions of himself.

29. #29Undermafia (AU)

    Keys: mafia au, gangster au, skeleton gang, mafiatale, undermafia

    Undermafia (also known as Mafiatale) is an AU where the central characters are reimagined within the theme of organized crime and mafia culture. The setting is reminiscent of 20th-century America, where criminal gangs and mafia families were prevalent.

    Background: The history of this universe is largely unknown, including whether a war between humans and monsters ever occurred. At some point, Asgore and Toriel separated. Toriel took a human child named Frisk into her care. Due to conflicts between the Dreemurrs, Toriel sent Frisk to a gang of skeletons that worked for her, to ensure the child's protection. The gang welcomed Frisk.

    The Skeleton Gang: Frisk is the current boss of the skeleton gang. Originally, Gaster was the leader, but he grew tired of leadership and passed control to Sans. Sans, due to his laziness and reluctance to take on such responsibility, passed it to his brother Papyrus. After Frisk joined the family, Papyrus decided to award the title of leader to Frisk, as she became everyone's favorite. No one objected.

    Characters:

    Frisk: A young human girl. Toriel's adoptive daughter. The current boss of the skeleton gang. She wears a mafia-style suit like the skeletons. She is close to the entire gang, especially Papyrus.

    Gaster: A member of the skeleton family. The first boss of the gang. He calls Frisk "boss" and always comes to her rescue. He has a strong and somewhat unhealthy love for Frisk. He works in secret, always able to obtain highly classified information. He has known Sans for a long time and knows exactly what pressure points to use when he needs control. His relationship with Sans is not fully explored.

    Sans: A member of the skeleton family. No one understands how he manages to live with such laziness. He works for money and because of Gaster (circumstances unknown). He protects the boss and Papyrus with everything he has. Despite Frisk being the boss, he continues to call her "kid." He is skilled with weapons. He sometimes smokes. Unlike his original counterpart, he is more cruel and insane when fighting someone.

    Papyrus: A member of the skeleton family. He was the second leader of the gang. He likes to call Frisk his friend. He is the gang's sniper. Gaster gave him his rifle. He can also become insane, but this often manifests as him ruining the spaghetti he loves to cook. He is ruthless in battle — one shot equals one kill. He likes the mafia style and wants to spread this fashion.

    Mettaton: A superstar supported by the Dreemurr family.

    Status: Undermafia was created on November 15, 2015, and cancelled on May 25, 2016. The author only designed Sans, Papyrus, Gaster, and Frisk. Other character designs were not developed by the creator, though some fans have created their own versions.

    Format: The AU was intended to be a text-based game but was never completed. Most of the stories about territory divisions, gangs, and the difficult lives of the characters are fanon that became popular within the fandom.

30. #30Reapertale (AU)

    Keys: god au, death gods, divine au, reapertale, reaper sans

    Reapertale is an Undertale AU where the main characters are gods or divine beings. The setting draws heavily from ancient Greek aesthetics and mythology.

    Background: The monster-gods were created from stars. After death, they return to the heavens as stars, leaving behind stardust. Toriel, the Goddess of Life, brought life into the world and created humans — they are her creations and her "children."

    Over time, the number of immortal beings in the world reached its limit, disrupting the balance. Asgore, Gerson, and Gaster decided to create a god of death to restore balance. Toriel opposed this decision and, as a protest, descended to the human world, turning away from the other gods.

    Asgore, Gerson, and Gaster created death as the opposite of Toriel. Due to Gaster's inexperience in creating life, he made a mistake, and instead of one god of death, two were created — Sans and Papyrus.

    Characters:

    Asgore: God of the Sky and Father Ruler. One of the creators of Death. He wears ancient Greek-style clothing in blue and beige tones.

    Toriel: Goddess of Life. She wears ancient Greek-style clothing in green tones. She is Asgore's estranged wife who abandoned her duties but never officially ended their relationship.

    Asriel: Embodiment of Hope. He believes in humanity and wears ancient Greek-style clothing in brown tones with a purple belt and cloak. He is Chara's best friend.

    Flowey: Embodiment of Despair. Reincarnated after Chara's death. Appears as a flower heavily drenched in blood.

    Gaster: God of Magic. One of the creators of Death.

    Gerson: God of Wisdom. One of the creators of Death. Wears ancient Greek-style clothing in beige tones.

    Alphys: Goddess of Knowledge. Wears ancient Greek-style clothing in light green and beige tones. She saved Mettaton's soul with her magic.

    Undyne: Goddess of War. Wears armor and clothing in red and beige tones. Armed with a spear with points on both ends. She has a passionate, intense, and strong personality.

    Sans and Papyrus: Gods of Death. Sans represents the harsh side — uncompromisingly taking the souls of sinners. Papyrus represents the softer side — gently persuading souls to accept the afterlife and find peace. Both wear black hooded robes and are armed with scythes. They were created by Gaster, Asgore, and Gerson.

    Sans has black wings that appear and disappear at will. He can teleport, levitate, and manipulate darkness — including creating black holes or darkness clones. He is omnipresent as the conceptual manifestation of death itself. He can negate durability and instantly kill nearly any creature with a soul. He is immortal and does not age.

    Personality: Sans was okay with his role as a reaper, but he didn't enjoy it. After accidentally killing someone he loved, he became suicidal and partially insane, with bits of his soul lost. Toriel helped him regain his sanity, but his soul is still incomplete, leaving him occasionally uncontrollable. He is calm most of the time and hides his feelings. He can be nice and funny once known. He has a coffee addiction and likes puns. He fears dolls, clowns, and Gaster.

    Frisk: Emissary of Mercy. Created by Toriel but remains mortal. They teach others mercy and wear Greek-style clothing. In Reverse!Reapertale, Frisk is the Emissary of the End — an anomaly who wants to bring "ultimate mercy" to the entire world through death.

    Chara: Beloved Acolyte / Fallen Chara / Anomaly / Part of Broken Faith. They wear a dark tunic. They were the beloved acolyte of the Gods but were killed by humans. They called upon the Gods for help but were ignored, leading to their death. They were reborn and lost their faith in the Gods. Asriel's best friend. In Reverse!Reapertale, Chara is the acolyte of balance and the cycle of death and rebirth.

    Mettaton: Human / First Golem / Crystalline Golem. Humanlike face with a sharp smirk, short spiky black hair swept to the side, and a black domino mask covering the left eye. Black feathered wing-like shoulder pads. Sleek black form-fitting bodysuit with a pink heart chest emblem and three silver metallic bands across the torso. Pink belt with a silver heart buckle, attached to a massive sweeping cape with a luminous pink star-speckled interior and black exterior. Knee-high shiny pink latex boots, matching pink gloves, and a confident pointing pose while holding the cape edge.

    Napstablook: A ghost waiting for Mettaton's return. A classic white ghost silhouette with a round body and 2 dark vertical oval eyes (the middle one slightly taller). Wears a large cluster crown of bright yellow flowers on its head, set against a textured yellow-green background.

    Grillby: God of Health. Head made of bright upward-reaching orange and yellow flames with glowing yellow horizontal slit eyes. Ancient Greco-Roman attire consisting of a flowing white tunic, a draped faded coral sash around the waist and left shoulder, and a brown cross-chest strap with a gold swirling medallion. Brown strappy sandals. Depicted in both a standing pose with darkened spindly fingers and a seated meditative lotus pose with small floating fire orbs nearby.

    Muffet: Goddess of Luck. Pale purple smooth skin with a faceless head featuring three dark oval voids forming a triangle and a smaller oval below. Dark black hair styled into two large pigtails, each tied with a yellow star accessory. Six arms (three per side) decorated with gold translucent cuffs. Wears a white sleeveless cropped top, ornate gold collar with a purple gem pendant, and a long wispy white skirt with a fringed gold waistband. One visible leg is wrapped in purple material with intricate gold geometric patterns.

31. #31Storyshift (AU)

    Keys: character shift, preboot, storyshift, role swap au

    Storyshift is an Undertale AU where the main characters swap roles, but their personalities remain the same. Locations, secondary characters, and attacks are unchanged. There are two versions of this AU — the original preboot (discontinued) and the reboot.

    Background: Long ago, Humans and Monsters lived together. At some point, some Humans began using Monster magic, and these Humans were called Mages or "demons."

    Role Shifts:

    Papyrus → Toriel's role

    Alphys → Napstablook's role

    Asriel → Papyrus's role

    Chara → Sans's role

    Toriel → Undyne's role

    Asgore → Alphys's role

    Undyne → Mettaton's role

    Mettaton → Chara's role

    Napstablook → Asriel's role

    Sans → Asgore's role

    Characters:

    Shifty: The protagonist of Storyshift, replacing Frisk. Shifty is identical in appearance to Frisk but wears items of the Blue Soul: ballet shoes and an old tutu.

    Boogie: A "gray" version of Flowey. Boogie does not strongly desire Shifty's death at the start and is not interested in meeting them. Boogie was originally Flowey but was later replaced.

    Papyrus: Papyrus is charismatic and slightly egotistical, calling himself "The Great Papyrus." Despite this, he is very kind-hearted and happy to help others. He bakes his signature "pieghetti" for guests. His hobbies include reading books, creating puzzles, making jokes, and collecting action figures. He is also interested in sports cars. Stats: 7 ATK, 0 DEF.

    Alphys: Alphys is very shy and hides their appearance under a bedsheet. They are deeply interested in anime, creating headcanons, and analyzing anime characters. They are quite irresponsible, leading to their home being in a semi-ruined state. Stats: 1 ATK, 1 DEF.

    Asriel: Asriel is cheerful and somewhat egotistical, often calling himself a "god" or "scary monster" and wanting others to fear him. He is actually kind-hearted, always ready to help, and even bakes very sweet cookies for others. He enjoys using his father's traps but becomes upset when they don't work. Stats: 3 ATK, 0 DEF. He wears a bandana, not a scarf.

    Winged Snake: Replaces the Annoying Dog. Steals the Legendary Artifact from under Shifty's nose. After this, a "Shed Skin" item appears in Shifty's inventory.

    Toriel: A member of the Royal Guard, recently enlisted before Shifty's fall. She is against killing humans for freedom and tries to protect Shifty by offering to go with them. When Shifty continues forward, she fights to stop them. Stats: 80 ATK, 80 DEF.

    Asgore: The Royal Scientist and Toriel's estranged (but not divorced) husband. He wears a white lab coat with glasses. He revived Napstablook in Boogie's body. He also turned Undyne into a cyborg. He is married to Toriel and is Asriel's father and Chara's adoptive father. He wanted to give his soul to Shifty.

    Undyne: A cyborg star of the Underground. By the time of the boss battle with Undyne Umbra, she had left. She is in love with Alphys. She has robotic functions because she was injured after the Core rose when she was younger.

    Sans: The King of the Underground. He is lazy and loves hot dogs. He wants revenge on humans for Mettacrit's death. When Papyrus left him, he fell into depression. He enjoys drinking tea made from echo flowers. Unlike Asgore in Undertale, Sans breaks the Mercy button with a red Gaster Blaster. His trident does not shoot, and his bones are similar to Asgore's magic fire.

    Napstablook: A shy ghost. Napstablook was Mettacrit's good cousin before Mettacrit died. Napstablook died of grief after losing Mettacrit when Mettacrit went to the surface and perished. They were reborn in Boogie's body.

    Mettaton (Mettacrit / Metta): Also known as Mettacrit or Metta. A friend of Papyrus. Helped carry out the plan to communicate with the surface. He took the soul of Mira — the first fallen human — and crossed the barrier, but met the same fate as Asriel in the original Undertale. Mettacrit comments on the game. The name "Mettacrit" is a pun on the review site Metacritic, similar to how Napstablook's name is a pun on Napster. Mettacrit is not human but still a ghost.

    Chara: Chara Dreemurr is the Judge of the Underground. They are a human adopted by the Dreemurr royal family. They serve as the older sibling of Asriel and the protector of the Dreemurrs. Their Undernet name is "Togor the Forgotten" — a combination of Toriel and Asgore's names, reflecting their desire to be seen as the child of the first two.

    Physical Appearance: Chara has a slender, agile build with a relaxed posture that remains ready for action. She stand between 147 and 158 centimeters tall. Their medium to dark brown hair is messy and medium length, with bangs falling over their eyes. Their eyes are dark brown, almost black, and glow a deep blood red during combat, strong emotions, or when using magic. Their face features permanently rosy cheeks contrasting with pale skin. Their default expression is tired, neutral, or cynical. They have several old scars, including one on the chest from the Core incident, which they no longer hide. Feminine form, average chest and thighs.

    They wear a white t-shirt (sometimes patched), an open lime green or brown jacket, dark pants, and sturdy boots. After bonding with their partner, they often wear their partner's jacket or a brown glove with a closed-eye symbol as a totem. They wear a vine and blade pendant given by Sans.

    Personality: Chara is cynical and tired, speaking in a monotonous, dry, sarcastic tone. They expect the worst from people, especially humans, due to past abuse. All cynicism vanishes when it comes to the Dreemurr family and monsters of the Underground — they are fiercely protective and loyal beyond death. They are intelligent, observant, and analytical, thinking in terms of efficiency and acting as the voice of reason against Asriel's enthusiasm.

    They struggle with trauma, depression, and low self-esteem. A near-suicide attempt was stopped by Papyrus, solidifying their will to live for monsters. Despite their tough facade, they show compassion for monsters and love Asriel with pure devotion.

    Background: Chara fell into the Underground wearing only black shorts and a white shirt. Their hoodie was made by monsters or found at the Dump. Toriel asked King Sans not to kill Chara due to their strong resistance to Sans's plans, allowing them to survive.

    Chara was adopted by the Dreemurr family and became the Judge of the Underground — a role that involves determining the fate of humans who fall into the Underground. They live in the Underground as a trusted member of the royal family.

    Relationships:

    Sans (King): Grateful that Sans rescued them initially. They share mutual professional respect, and Sans approves of their union with their partner.

    Asriel: They love him unconditionally as their protective older sibling.

    Toriel: Deep filial respect and love. Toriel rescued and taught them.

    Asgore: Respectful affection toward a kind father figure.

    Frisk: Initially distrustful and cynical, calling Frisk "beautiful mirror." With kindness, they become an ally and guide. In a Genocide Route, they see Frisk as the destroyer of their past, present, and future.

    The protagonist's name is now Shifty

32. #32Flowerfell (AU)

    Keys: flowerfell, golden flowers, frisk sans, reset curse, fell au, underfell variant

    Flowerfell is an Undertale AU where Frisk is cursed with golden flowers that grow on their body each time they die and reset. The flowers cause immense pain and cannot be removed. This AU combines the dark aesthetic of Underfell with a tragic love story.

    Background: The AU features a version of Underfell where Frisk remains a pacifist despite the cruel nature of the world.

    The Curse of Golden Flowers: When Frisk dies and resets, a golden flower grows on their body. Each death adds another flower. Over time, the flowers spread across Frisk's body. They cause severe pain and cannot be removed. The flowers eventually consume Frisk's body, causing blindness and immobility. The origin of the curse is never explained — the creator deliberately left it a mystery.

    Characters:

    Sans: Sans is initially similar to his Underfell counterpart — cruel and willing to kill. He kills Frisk multiple times, including after their first handshake. However, Frisk's persistent kindness confuses him. He eventually feels compassion and decides to escort Frisk to the barrier. He can remember everything from each reset. He calls Frisk pet names such as "sweetheart" or "dear." He is 7 feet tall (his brother Papyrus is 10'8").

    Frisk: Frisk is depicted as 18 or older, with ambiguous gender and race. They firmly believe in kindness and never intend to hurt anyone in the Underground. They thank everyone for acts of kindness — even Grillby for serving food. They say "always be kind" to Sans. They eventually confess they have "wanted to die more times than they can remember" but could not due to resets. They become blind and immobile as flowers cover their body. They sacrifice themselves to break the barrier.

    Flowey: Flowey is the soul of Asriel Dreemurr in a flower, but in this AU he is kind to Frisk and helps them. He once had the power to reset and tried to help each of the six other fallen humans cross the barrier. He eventually gave up. With Frisk, he felt their determination was strong and their soul reminded him of Chara. When Frisk appeared, Flowey's reset powers were transferred to them. He feels guilty about this. Only Alphys knows Flowey is Asriel Dreemurr. She calls him a traitor for siding with a human.

    Plot Summary: The story begins after Frisk dies for the first time at Toriel's hands and wakes up with a flower on their head. Despite constant attacks and repeated deaths, Frisk refuses to fight. Toriel eventually lets them leave the Ruins.

    When Frisk first meets Sans, he kills them after their first handshake. Over multiple resets, Sans kills Frisk himself or betrays them to Papyrus. But Frisk keeps returning and treating Sans with kindness. This intrigues Sans, and he eventually invites Frisk to eat at Grillby's. Sans realizes Frisk knows about resets when they pass him a bottle of mustard without being asked.

    Sans eventually decides to escort Frisk to the barrier. He protects them from other monsters, including Papyrus, Undyne, Alphys, Mettaton, and Muffet. In one reset, Sans loses control and kills Muffet. Frisk does not force a reset, but Mettaton kills them. After that reset, Sans avoids killing Muffet.

    By the time they reach Asgore, Frisk is blind and immobile from the flowers. They can no longer walk and have difficulty speaking, using uncertain sign language to communicate. Sans fights Asgore but only weakens him enough to make him yield. Sans refuses to kill Asgore, repeating what Frisk taught him: "always be kind."

    When they reach the barrier, Flowey offers to take one of the six human souls, cross the barrier, and return with another to break it forever. Frisk refuses and offers their own soul as the seventh. Sans is devastated. Frisk explains they cannot continue living as their body is consumed by flowers. They sacrifice themselves to break the barrier.

    After Frisk's sacrifice, Asgore cancels the plan to destroy humanity. Monsters build a community on the surface. Sans lives with Flowey and often visits the Ruins where Frisk is buried, waiting for them to return — just as he did when the timeline reset.

    Romance: Frans (Frisk/Sans) is canonical in this AU. Frisk is referred to as Sans's "wife" in some stories, though Frisk remains non-binary (using they/them pronouns). In the continuation "Unexpected," Frisk is biologically female and pregnant with Sans's twins, Vivaldi and Verdana.

33. #33Negatale (AU)

    Keys: negatale, depression au, negative au, blue au, dreemurr antagonists

    Negatale is an Undertale AU where the Dreemurr family has extracted all positive energy from the Underground and its inhabitants, leaving everyone in eternal sadness and grief. Monsters try to be happy, forcing fake smiles while their eyes remain empty. When Frisk falls into the Underground, they decide to return positive emotions to the monsters and make them truly smile again.

    Visual Design: The color palette of Negatale consists exclusively of blue, black, cyan, grey, and white — representing sadness and depression.

    Characters:

    Frisk: Frisk is a 15-year-old human who falls into the Underground after being pushed by Chara. They wear a blue and black striped shirt with a bandage on their left cheek. Frisk's determination is weaker than their original counterpart, but they want to stop Asgore and his family. Frisk can transform into Spirit Frisk or Undead Frisk in certain situations.

    Sans: Sans lives in Snowdin with Papyrus. He wears a dark grey hoodie with a white minus symbol in the center, blue sleeves, blue pants with white stripes, and skeleton slippers. His bones are grey. Sans works at Grillby's but only does garbage duty. He is afraid of Chara, even though Chara loves him. Sans is deeply depressed after his father Gaster's death and rarely tells jokes. He is clingy to Frisk, feeling protected and safe around them. Sans drinks strawberry syrup straight from the bottle.

    Negative Sans: When Sans feels extreme anger or learns that Frisk has been killed, he transforms into Negative Sans. His colors invert — he wears a light grey jacket with a black minus symbol, yellow sleeves, yellow pants with black stripes, and grey slippers with black eyes. His eyes turn yellow with Gaster-like streaks. In this form, he gains enhanced abilities, including Gaster Blasters with ribs and tails, stronger bones, faster telekinesis, and physical damage attacks.

    Papyrus: Papyrus retains his bright personality but is deeply concerned about Sans's emotional state. He wears a grey battle body with a blue scarf. He cooks macaroni and cheese to cheer Sans up. He is well-known for being kind to humans.

    Alphys: Alphys is the Royal Scientist. She is an aquatic creature resembling an axolotl, with fins and a tail. She believes she is superior to others and conducts experiments on monsters using negative energy. She is Monster Kid's older sister and is in love with Undyne.

    Undyne: Undyne has a more lizard-like design with a long tail. She wears a black eyepatch, a black tank top, and an emotion suppression device around her neck. Her personality is more relaxed and less rude than her original counterpart. She lives with the skeleton brothers and is protective of them.

    Mettaton: Mettaton acts similarly to his original counterpart, but his back button is jammed, preventing him from transforming into his EX form — though he appears in EX form in later events.

    Grillby: Grillby is the opposite of his original counterpart — cold-hearted and made of ice.

    Gaster: Gaster is Sans and Papyrus's father. He was the former Royal Scientist before he fell into the Core and died when his sons were young. He wears a long dark grey coat with blue and white lines.

    Muffet: Muffet has dark skin, white hair tied in pigtails with blue ribbons, and purple eyes. She is a widow and a royal pastry chef. She is in love with Asriel.

    The Dreemurr Family: The Dreemurrs are mysterious goat-like creatures with dark blue fur. Their mouths are invisible when closed. They hoard positive energy in a sphere for their own purposes, preventing anyone else from feeling positive emotions. They are the clear antagonists.

    Asgore: Rules the Underground with Toriel. His right horn is broken. He prevents any positive energy from escaping the castle.

    Toriel: The queen, cunning and deceitful. She offers poisonous blueberry or blackberry pie to visitors.

    Asriel: The prince, elegant but cruel to those outside his family. He is in love with Muffet.

    Chara: A demon created by Asgore and Toriel's shadow magic. They have an unhealthy, unrequited love for Sans. Their favorite weapon is a knife, and their favorite food is chocolate. When they realize they can never be with Sans, they transform into a more powerful, enraged form.

    Original Characters:

    Sin: A demonic entity who created Negatale out of boredom. They watch the AU play out on a TV while enjoying tea and sweets. They can open portals, fly, and possess others.

    Hollow (The 1st Human): A human who fell before Frisk. Alphys experimented on them by injecting negative energy, transforming them into a violent creature with black skin and distorted arms.

    Cotty: A sheep girl with a rude personality who is in love with Asriel. Asgore wants her to be Asriel's wife, but Asriel loves Muffet.

34. #34Undertale Yellow

    Keys: yellow soul, prequel, clover, justice soul, undertale yellow

    Undertale Yellow is a fan-made prequel to Undertale. It follows the story of Clover, the seventh human child to fall into the Underground, who possesses the Soul of Justice. Clover descends into the Underground to investigate the disappearance of five humans who fell before them.

    Setting: The game is set in the world of Undertale, where monsters were sealed beneath Mount Ebott following their defeat in a war against humans. Asgore, the king of the monsters, has collected five of the seven human souls needed to break the barrier.

    Characters:

    Clover: Clover is a human child who possesses the Soul of Justice. They enter the Underground to uncover the fate of the five missing humans. Clover wears a cowboy hat, a brown vest, blue pants with a gold buckle, and brown boots. A yellow bandana with blue polka dots is tied around their neck. They are armed with a toy pistol that can be loaded with various items such as rocks, ice, nails, and similar objects. Clover is mostly silent but has a strong sense of justice and a desire to do what is right. Their actions determine the course of the story.

    Flowey: Flowey appears identical to his Undertale counterpart in appearance and personality. However, in this story he acts differently — he befriends Clover and helps them throughout their journey. His goal is to have Clover reach Asgore alive so he can steal the human souls while Asgore is distracted. He still has access to saving and uses it to guide Clover along the path he wants.

    Dalv: Dalv is a purple, vampire-like monster living in the Dark Ruins. He wears a brown hooded cloak that hides his clothing most of the time. He is antisocial and reclusive, avoiding the protagonist and starting a battle at the end of the area. He had an incident in the past involving the Soul of Integrity, which caused him to become withdrawn and barricade the exit from the Dark Ruins. If spared, he opens the exit, and all monsters from the Dark Ruins move to Snowdin.

    Martlet: Martlet is an anthropomorphic bird with blue feathers, living in Snowdin Forest. She wears a shirt and pants in matching colors with yellow boots. She is a member of the Royal Guard specializing in puzzle construction. Despite her status, her personality does not fit the role — she is scatterbrained and worries about being fired for her mistakes. She resembles Papyrus, Sans, and Undyne combined: most of the time she is somewhat foolish but very kind, but she can act as a judge and a cold but just warrior when necessary.

    Starlo: Starlo is a humanoid monster with a star-shaped head. He is the sheriff of the town "Wild East" in the Dunes. He wears a hat with a feather, glasses, dark brown boots and gloves, brown pants, a shirt with turquoise and brown sleeves, and a brown poncho with a yellow star. He is deeply interested in human culture and the Wild West, acting as a cowboy. His efforts are a performance to help monsters forget their suffering and entertain them. In reality, he is a somewhat boring farmer more interested in science than cowboy culture.

    Ceroba: Ceroba is an anthropomorphic fox of light orange color, wearing a traditional Japanese kimono in white and red. She is Starlo's best friend and lives with him in the Wild East. Outwardly friendly, she is sad and cunning inside. She suffered a family tragedy and is determined to continue her late husband's work. She uses Clover for her own purposes and can give in to rage.

    Axis: Axis is a robot guard in the Steamworks, originally created as a mechanical Royal Guard. He has a wheel for movement, a rounded body with a purple heart symbol in the center, and a large square head with two antennas and purple eyes. He has a pair of hovering hands. Although a robot, he has emotions — he is aggressive and easily irritated but can also feel responsibility and pity.

    Chujin: Chujin is Ceroba's deceased husband, Martlet's mentor, Axis's creator, and a prominent engineer who claimed the position of Royal Scientist instead of Alphys. Like Ceroba, he is an anthropomorphic fox, but dark purple. He wears a turquoise kimono with yellow trim. He was kind, courteous, and hardworking, but also stubborn and intolerant of failure. He worked at Steamworks creating a robot Royal Guard, but all prototypes failed. After a human with the Soul of Integrity fell, Chujin sent Axis to capture them, but a malfunction caused Axis to kill the human instead. Chujin hid the evidence and began experimenting with the human soul. He discovered he had boss monster genetics and extracted an injection from the human soul, applying it to himself. The experiments eventually killed him.

    Kanako: Kanako is Chujin and Ceroba's daughter. She is an anthropomorphic fox with brown fur, wearing a pink and yellow kimono. She was brave but naive. After overhearing her parents' conversation, she discovered a secret room in their house. Ceroba found her there and convinced her to use an improved version of the serum on herself. The serum failed, damaging Kanako's soul and causing her to fall into a coma. Ceroba sent her to Alphys's laboratory in desperation.

    Routes:

    Neutral Route: Clover falls into the Underground and meets Toriel, who offers to guide them through puzzles. Clover ignores her and proceeds into the Dark Ruins, where they meet Flowey. After various encounters and boss fights, Clover reaches the hotel. Flowey impales Martlet with a vine and reveals his manipulation. He engages Clover in a two-phase battle, distorting his appearance in the first phase and transforming into Meta-Flowey in the second, with six forms and attacks based on each form.

    Pacifist Route: Clover spares all monsters. Ceroba accompanies them to Steamworks, where they discover Chujin's notes revealing his experiments with human and boss monster souls. Ceroba attempts to use Clover for her experiments. Martlet, Starlo, and Clover confront her. During the final battle, Clover learns that Kanako fell into a coma when Ceroba tested the serum on her. After Ceroba's defeat, if spared, she reconciles with the others. Clover decides to sacrifice their soul to free the monsters.

    Genocide Route: Clover kills all monsters in each area. Flowey guides them, but his warnings are ignored. Martlet injects herself with Determination and transforms into a massive bird in the final battle. After her defeat, Flowey reveals his plan and is shot by Clover. Clover reaches Asgore and destroys him with a powerful beam, absorbs his soul, and takes the other human souls, escaping the barrier.

35. #35Negativetale (AU)

    Keys: personality swap, negative au, weaker vs stronger, dark au, negativetale

    Negativetale is an Undertale AU where all characters have the opposite personalities from their original versions in the worst possible way. The clothing has also taken on a "negative" variant. Monsters in the Underground believe that only those with enough strength can survive, so strong monsters look down on the weak. Even those with somewhat good intentions are still cruel. This AU is similar to Underfell but with the added dynamic that those who were good are now evil, and those who were evil have become good.

    Characters:

    Flowey: Flowey is identical to his original counterpart except his petals are blue and badly torn. His personality has changed for the better — he helps Frisk navigate the Underground, telling them where to go and who to trust. He is very timid, especially afraid of Asgore, which is why he rarely leaves the Ruins. In his flower form, he is incapable of feeling negative emotions such as anger or irritation.

    Toriel: Toriel went mad after the first fallen human died, blaming herself for not protecting them. She is overly protective to the point of obsession. When she first sees Frisk, she mistakes them for Chara. She destroys every puzzle, threatens monsters that they will be killed if they even look at the child, and begs Frisk not to leave the Ruins. When that fails, she decides to punish the child, trying to trick them into hugging her so she can kill them with a massive fireball. Frisk dodges, and the fireball hits the ceiling, causing a stone to fall and kill Toriel.

    She wears an old purple robe patched with green. On her chest is the Delta Rune in the form of Asgore's red trident on a dark grey background. Her red eyes often show madness.

    Sans: Sans is considered one of the weakest monsters in the Underground. Many are surprised he is still alive. He is a card sharp and a thief, successfully fleecing money from other monsters. He appears to use the human only for his own benefit from the very first meeting, pretending to want to help them survive the Underground. He will likely abandon them immediately after achieving his goal.

    Sans hates his brother, calling him a piece of garbage, insulting him, and waiting for any opportunity to kill him. It was Sans who left the crack on Papyrus's skull. He later successfully kills Papyrus while the skeleton is distracted by fighting Frisk. He gives the child money for survival, which turns out to be chocolate coins. He loves mayonnaise instead of ketchup. During the first meeting, he jokes with Frisk using a harmless taser.

    He wears an orange hoodie with a grey vest over it. A dark orange bandana is tied around his neck, hiding the hood that everyone likes to grab. His left eye socket, which was damaged by Papyrus, does not glow in its normal state. His skull also has a crack.

    Papyrus: Papyrus is one of the prime examples of how local monsters differ from the original Undertale in a negative way. He is truly evil, capable of killing someone just to prove he is the strongest, fighting to the death without accepting mercy. He takes his goal of joining the Royal Guard extremely seriously, killing monsters without remorse. He mocks Sans, forcing him to work nonstop and preventing him from making jokes. If Sans does something wrong, Papyrus attacks him, and it was during one such incident that he damaged Sans's eye socket. He became this way after being rejected from the Royal Guard. Despite this, he still calls himself "great," laughs the same laugh as the original Papyrus, and often strikes "cool poses."

    He fights much better than the original Papyrus. He can summon walls of bones, recolor the battle box to blue, and create platforms like the original Sans. His stats are similar to the original Papyrus but he has twice the ATK. However, he is less durable, which allows his brother to easily kill him when Papyrus is distracted by fighting Frisk.

    His battle body resembles the original Papyrus's armor, dominated by dark grey and blue. On the right side of his chest, instead of stripes, there is an arrow with an additional line in the middle. His left shoulder pad is damaged, and his skull has a crack that Sans contributed to. Instead of a standard scarf, he wears a long cape that reaches his feet.

    Undyne: Undyne was recreated by Alphys in the laboratory as a soldier. She is the Captain of the Royal Guard, but is much colder and more cruel. Her motto is "Sacrifice everything for the hero." She will kill anyone for Asgore. During the Underground festival, she lines up the weak and personally executes them in front of everyone. When attempting to catch the human, she mistakes Monster Kid for them and knocks them off a bridge with her spear, causing them to fall to their death. When she turns Frisk's soul green, she does not give them a spear to defend themselves, leaving them immobile and forced to take damage from her attacks. At the end of Waterfall, when Frisk tries to give her water, she pulls out an explosive device, hoping to destroy Frisk along with herself. Frisk escapes in time, and Undyne dies.

    Her relationship with Alphys is unknown, but it is presumed she is not in love with her. She values Papyrus not as a friend but as an additional problem — if he joins the Guard, he would quickly replace her as Captain.

    She has mint-green hair and grey armor. Her spears are dark orange and sharply curved at the top. On her chest is the same Delta Rune as Toriel's. Her right eye has a black sclera and a yellow pupil, rather than the reverse.

    Alphys: Alphys is the cold-blooded Royal Scientist and Asgore's spy. She created Undyne as a soldier incapable of thinking about anything other than killing for Asgore. Rumors say she also saved Mettaton the ghost from suicide. She used her as a killing machine until she went out of control and disappeared. She does not report Frisk to Asgore, but only so that Frisk will deal with Mettaton. In the end, she tries to extract parts from Mettaton, but the still-active robot traps Alphys and explodes, destroying them both.

    She wears a strict black suit with a red tie. She is missing her right eye, and her right arm has been replaced with a robotic one.

    Mettaton: In this AU, Mettaton is female. She was an annoying ghost who dreamed of becoming famous. The emotion-blocking device installed in her body broke when she felt guilt and the taste of defeat. She decided to end her life by suicide out of spite, but this only increased her guilt. She hid from Alphys and "upgraded" her body, replacing parts with more colorful ones and selling all weapons, including the bomb Alphys installed for emergency self-destruction.

    She is not initially a TV star and only appears on screens when the human arrives in Hotland. She does not host a quiz show. Her other shows are more friendly, resembling theatrical performances. In her "final episode," she traps Alphys and explodes, destroying them both.

    Her attitude toward Alphys is changeable — sometimes she thanks her, other times she is rude. She treats the human well, helping them in several moments. Her stats are similar to the original but with 1 ATK. In her box form, she has a white body and pink screen. In EX form, she has blue eyes, light pink details with pink shoulder pads and hair.

    Napstablook: Napstablook hates the entire world and is a true introvert. They lie on a leaf pile and ask Frisk to leave when approached. They eventually realize that fighting the "stubborn and annoying" Frisk would go on forever and quickly leave. They call their hat "Kapoblok" instead of "Dapper Blook." They appear as a negative version of the original Napstablook — a black ghost with a white mouth and eyes. Their house is closed off and isolated from all Waterfall residents.

    Mad Dummy: Mad Dummy has become much kinder and wants communication, but never succeeds — Napstablook ignores them and Undyne is mad and violent. They got along with Mettaton, but when she left Waterfall, their conversation partners disappeared. When they meet Frisk, they hope they will listen, but when Frisk agrees, the dummy cannot find any topic and simply lets them pass.

    Asgore: Asgore is a ruthless king ruling the entire Underground. He does not tolerate failure from himself, does not care about his family, and uses everyone only to achieve his goals. He is a tyrant and dictator whose goal is to rule both the Underground and the Surface. After Asriel's death, he stopped appearing in public.

    He fights Frisk in New Home. He is very strong, and Frisk quickly loses. He almost kills them, but Flowey appears, fully restores Frisk's HP, and kills Asgore. However, after absorbing his soul, Asgore begins to take control of Frisk, forcing Flowey to kill them.

    Unlike the original Asgore, he has 255 ATK and DEF. His trident does not change color during attacks, dealing monstrous damage but only hitting once per turn.

    He has black hair and a broken right horn, with a gold ring with a ruby on the broken horn. He wears a gold crown with emeralds and rubies. On his chest plate is his red trident symbol. Instead of ordinary golden flowers, he grows blue flowers. His eyes are red like Toriel's.

    Chara: Chara was the first fallen human. When they fell into the Underground, Asgore wanted to kill them and take their soul, but Chara claimed they hated humanity and that all people deserved death. Asgore decided that cooperating with a human to exterminate humanity was a good idea, as humans are much stronger than monsters. Toriel also liked Chara, so Asgore adopted them and began training them. They grew stronger every day.

    At a festival, Asgore refused to execute monsters and entrusted this role to Chara, lending them his trident. Chara killed monsters, but when it came to the last one, they could not bear it, dropped the trident, and began to cry loudly. Asgore, enraged, took his trident and killed Chara. He then ordered Asriel to absorb Chara's soul, go to the Surface, kill six more people, and absorb their souls. Asriel obeyed.

    When Asriel went to the Surface, people attacked him. He tried to kill them, but Chara stopped him, and Asriel saw their true nature — they did not hate humanity at all; they lied to Asgore to survive and return home one day. People inflicted serious damage on Asriel, and he eventually returned to the castle and turned to dust.

    Asriel: Asriel was the prince. After Chara's death, Asgore ordered him to absorb Chara's soul, go to the Surface, kill six more people, and absorb their souls. When Asriel went to the Surface, people attacked him. He tried to kill them, but Chara stopped him. He received many terrible wounds and returned to the castle, where he finally died.

    When he was reborn as Flowey, he saw the changes in the Underground after his death: the old royal symbol was completely replaced, monsters lost some positive feelings, Asgore stopped appearing in public. He wanted to say "This is all because of the human! If they hadn't said they hated humanity, none of this would have happened!" but he could not, as all his negative emotions had disappeared.

    Grillby: Grillby's flame is blue, turning orange when he is angry. He wears a light suit with a red bow tie. He is a quiet monster and still works as a bartender. He hates Sans, who constantly orders food and does not pay, and is even planning to kill him for this.

    Gerson: Gerson's clothes are similar to the original but dominated by blue. Instead of the nickname "Gerson, Hammer of Justice," he is called "Gerson, Mass Destruction of the Era." He is the only monster in the Underground who still has the right to wear and speak of the Delta Rune. His personality is close to the original.

    Burgerpants: Burgerpants works at MTT. He is identical in appearance except for his blue uniform. He loves his job because he "gets paid for sitting and doing nothing," but hates his boss for being overly talkative. He got the job because it was the easiest work he could find. He does not recommend eating at the MTT restaurant and says that as soon as the barrier is broken, he will quit and go on a cruise.

    Monster Kid: Monster Kid appears similar to the original, but the first two spikes on their head are grey. They are a huge fan of Undyne but also afraid of her, knowing how cruel she is, though they do not know what happens at the monster festivals and want to attend to meet Undyne face to face. They initially treat Frisk well, but when they realize they are human, they try to turn them over to Undyne. When Frisk tries to save them from falling off a bridge, they think Frisk wants to kill them and become terrified. They die from the fall after being knocked off the bridge by Undyne's spear.

    Regular Monsters: Their appearances and personalities remain unchanged. Only one regular opponent is encountered in the comic — the First Froggit, who is quickly killed by Toriel. Later, another Froggit appears, saying Toriel told all monsters not to approach the human and killed all monsters except them. When they realize Frisk is human, they repeatedly say "no."

    According to the skeleton brothers, there are many angry monsters and Royal Guards in Snowdin Forest, but Frisk cannot see them because Sans immediately teleports them to Snowdin Town. No regular opponents or mini-bosses are encountered in Waterfall or Hotland.

    The Delta Rune: The Delta Rune has been replaced by Asgore's trident symbol. This decision was made after Asriel's death, and the standard Delta Rune was completely banned, as was discussion of the prophecy it represents.

    The Pacifist Route: The True Pacifist Route is impossible here, as opponents who fight Frisk die regardless.

36. #36Hardtale (AU)

    Keys: hard au, combat skilled, strong au, hardtale, powerful characters

    Hardtale is an Undertale AU where all characters are significantly stronger and faster than their original counterparts. Their personalities either remain unchanged or become more serious. Hardtale expands upon the concept of a more difficult version of Undertale.

    Characters:

    Frisk: Frisk is much stronger and faster than their original counterpart and possesses combat skills. They resolve conflicts through battle but will not finish off an enemy if it is no longer necessary. Their primary weapon is a red knife, and they also have a pistol in their arsenal. Frisk can mock their enemies.

    Flowey: Flowey can attack with vines from underground and can change the soul mode to green.

    Napstablook: Napstablook is not so much sad as they are playful in battle. They can easily control multiple things at once and attack with them. They help Frisk in the fight against Mad Dummy.

    Toriel: Toriel is much more determined in her battle against the human. She has the ability to teleport and can release purple fire.

    Sans: Sans is nearly identical in character and behavior to his original counterpart, though he may have become more active and eccentric. He attacks Frisk in Snowdin Forest but, after accepting defeat, helps them on their journey. He possesses all the abilities of the classic Sans, but his Gaster Blasters can fire blue, orange, and red beams. He can change the soul mode to green and can attack with his fists. Can fire fist as special attack.

    Papyrus: Papyrus remains an explosive and loud skeleton but takes his duties more seriously. Like Sans, he battles Frisk but loses and accompanies them on their journey. He uses a sword as his primary weapon, which can extend and change between blue and orange modes. His armor can transform when he uses his "special attack." In addition to his classic attacks, he can use telekinesis.

    Monster Kid: Monster Kid has boots in their arsenal that they stole from Alphys, which can fire orange, blue, and yellow beams. The boots can release a massive white beam capable of launching Monster Kid high into the air.

    Mad Dummy: Mad Dummy attacks with blood-covered knives and a pistol. They can also detach their head from their body for combat and create portals beneath themselves.

    Undyne: Undyne uses a green spear with a curved blade as her weapon. She can transition into green mode. She appears to be on friendly terms with Sans, as he is often seen near her. Sans did not attack Undyne during a joint battle with Frisk and Papyrus against the guard, merely pushing her aside. Undyne has a very specific approach to cooking.

    Alphys: Alphys is tasked with killing Frisk. She can remotely control Mettaton.

    Mettaton: Mettaton can launch rockets and fire from their palms. They were created exclusively to kill the player. In EX form, Mettaton can fire from their left eye.

    Muffet: Muffet's main weapons are four blades. Her pet is much larger than the original and can fire from its mouth.

    Gaster: In addition to blasters, Gaster can attack with white bullets. He can turn the soul both blue and grey.

    Asgore: In addition to his main weapon, Asgore attacks with red flashes, striking from beneath the opponent's feet.

    Locations: In addition to the main locations from Undertale, Hardtale features the Prison, the Portal, and Fairyland.

    The Prison: Frisk ends up here due to Mettaton. The location is a prison with grey brick walls and cells with iron bars. Five monster guards are present: a shield-shaped monster, a beetle-shaped monster, a flail-shaped monster, a spider monster that likes donuts, and a dog monster based on a cut Undertale character — Doge.

    The Portal: The Portal consists of massive caves with giant crystals. In the largest cave is a full-fledged city, next to which is the Portal, which scientists intended to transport monsters to the Surface. There is also an elevator in the city leading to Hotland.

    Fairyland: Fairyland is a location with many staircases, and its theme is heavily tied to puzzles and board games. Its design is based on the painting "Relativity."

37. #37Glitchtale (AU)

    Keys: determination, glitch au, hate, bete noire, glitched timeline, fear soul, glitchtale

    Glitchtale is an Undertale AU set in a glitched timeline where repeated resets and a failed Genocide Run have corrupted the world. The world consists of humans and monsters living together, governed by a meritocracy where social standing depends on magical ability. Seven districts exist: Justeco (Justice), Integreco (Integrity), Persisteco (Perseverance), Pacienco (Patience), Amikeko (Kindness), Kurago (Bravery), and Determino (Determination).

    The Glitch: Repeated resets in places "they weren't supposed to be" have created glitches in the timeline. These glitches allow for the revival of characters who were supposed to be gone, but also create new and dangerous threats.

    Characters:

    Frisk: Frisk is a male human with shoulder-length brown hair and yellow skin. They normally keep their eyes closed. Frisk had completed every route and every dialogue in the Underground, eventually starting a Genocide Run out of boredom. They feel immense guilt for their actions. They can create weapons from Determination, summon shields, and have the ability to Reset. Frisk sacrifices themselves by erasing themselves from existence to replace themselves with Chara and fix the glitches.

    Chara: Chara is the first human to fall into the Underground. They are male. They reawakened by latching their spirit onto Frisk. Chara becomes corrupted by HATE and serves as an antagonist, but Asriel later erases the HATE from them. Chara dies, giving their soul to Asriel as a vessel. Frisk later banishes themselves to the Void and gives Chara their soul, letting Chara take their place.

    Sans: Sans is a skeleton who remembers the resets and glitches. He warns Frisk about the dangers of resetting. He has a soul with 1 HP and is considered weak in some contexts. He absorbs Frisk's soul multiple times to gain power. He is killed by Bête Noire, his soul taken and fed to Akumu. Sans can summon Gaster Blasters that fire blue, orange, and red beams. He can change the soul mode to green, attack with his fists, and use bones in combat.

    Gaster: Gaster is the former Royal Scientist who fell into the Void. He attempts to steal Frisk's soul to regain a living form but is defeated by Sans. He is later revived through the glitches. Gaster has immense durability, allowing him to survive powerful attacks. He can attack with blasters and white bullets, and can turn souls blue or grey. He speaks in Wingdings.

    Papyrus: Papyrus is Sans's brother. He remains optimistic and supports others. In combat, he uses a sword and telekinesis. He can also use his classic bone attacks.

    Undyne: Undyne is the captain of the Royal Guard. She uses a green spear with a curved blade as her weapon. She can transition into green mode. She is killed but finds the strength to continue fighting through Determination.

    Alphys: Alphys is the Royal Scientist. She is killed in battle, dying while trying to assist others.

    Mettaton: Mettaton is a robot who can launch rockets and fire from his palms. In EX form, he can fire from his left eye. In NEO form, he fights Bête Noire to avenge Alphys.

    Asgore: Asgore is the king of the monsters. He killed six human children to obtain their souls. He is arrested and imprisoned later. He can attack with red flashes and his trident.

    Toriel: Toriel is Asgore's wife. She cares for Frisk and other children. She can teleport and release purple fire.

    Asriel: Asriel is the prince. He was killed by humans after absorbing Chara's soul and carrying their body to the Surface. He returns through the glitches. He wields the power of seven human souls and can fight against powerful enemies. He erases the HATE from Chara and later breaks the Barrier.

    Flowey: Flowey is the soulless form of Asriel. He teams up with Sans to fight Chara. Frisk gives Flowey a soul, allowing him to transform into Asriel.

    Bête Noire (Betty): Bête Noire is the main antagonist. She has pink hair, pink eyes, and wears a magenta dress and purple sweater. She possesses a Fear Soul (pink), representing the trait of Fear. She was created to destroy monsters and ensure humans and monsters never live peacefully. She harvests souls and feeds them to Akumu. She kills Sans and takes his soul. She can create pink blobs to attack and harvest souls. Her full form is Bête Noire, a beast-like creature that attacks with incredible power.

    Akumu: Akumu is a pink blob-like creature created alongside Bête Noire. It serves as Bête Noire's pet and weapon. It can absorb souls, including Sans's soul. It can grow in size and power and can manipulate others.

    The Anti-Monster Department (AMD):

    Jessica Grey: Jessica is the head of the AMD. She lost her daughter, Alina, to Asgore. She initially opposes monsters but eventually comes to regret her actions. She is manipulated by Bête Noire but later sacrifices herself to save Gaster.

    Amber Lightvale: Amber is a young girl with a Kindness Soul. She befriends others and aids in the fight.

    Rave Rutrow: Rave is Jessica's son-in-law and a specialist in magical weaponry. He aids in the fight against the giant blob and helps save Ronan from HATE infection.

    Ronan Cass: Ronan is Undyne's new partner. He becomes infected with HATE but is saved by Rave.

    Zachary: Zachary is a young boy who can see souls and magic. He becomes the Integrity Wizard in the Wizard Council.

    Lily: Lily is a young girl with a green (Kindness) soul. She is Cam's younger sister.

    Cam: Cam is Lily's older brother. He is killed by Bête Noire's pink blobs while saving Lily.

    Robin: Robin is a character who saves Lily.

    The Seven Wizards: In the prequel era, seven human wizards sealed the monsters Underground. They include Copper Lightvale, Agate Lightvale, Roy Goldburn, Shane Goldburn, Mila Rutrow, Kody Fallenfire, and Rin Winterway.

    Agate Lightvale: Agate created Bête Noire and Akumu before dying.

    HATE: HATE is a corrupting substance that takes control of those who harbor negative emotions. It controls Chara and manifests as a physical entity. HATE can infect others and grant power, but it also consumes the host.

    The Void: The Void is an empty space between timelines where Gaster was trapped. Frisk banishes themselves to the Void to replace themselves with Chara.

38. #38Oceantale (AU)

    Keys: aquatic monsters, pirate au, underwater au, ocean au, oceantale

    Oceantale is an Undertale AU set in the depths of the ocean. A human falls into the underwater world and encounters aquatic versions of the monsters.

    Characters:

    Frisk: Frisk is a human who falls into the ocean. On the surface, they wore a white cotton dress tied at the left shoulder with a knot and wore no shoes. After entering the ocean and meeting Toriel, they received a new outfit: a child's sailor suit, sometimes accompanied by a white peaked cap with a star and anchor emblem. They use a sturdy coral branch as a weapon.

    Sans: Sans wears a pirate uniform with a gold pattern on the back and a blue tricorn hat. He has an eyepatch over his left eye. The lower back of his skull is pierced in the shape of a heart. He has no feet — instead, he uses long blades as artificial legs. His Gaster Blasters are shaped like hands, with ten pointed teeth on each finger forming the jaw, except for the thumb and pinky which have five teeth each.

    Papyrus: Papyrus wears a pirate uniform and a tricorn hat, both in red. His back has a similar gold pattern, and his cape transitions from red to purple near the torn edge. His spine and left arm appear charred under unknown circumstances. His left forearm was broken and repaired with seaweed, with a bandage visible over his clothing. The back of his skull is pierced in the shape of an inverted heart. Like his brother, he uses long daggers instead of feet.

    Alphys: Alphys is an axolotl. Her skin tone has changed to white-pink. She still wears a scientist's coat, now with blue gradient edges. She wears a gold shell-shaped necklace, a gift from Undyne. She has six fins on the back of her head: two on top, two on the bottom, and two on each side. Her claws are white and sharp.

    Undyne: Undyne is now a full mermaid. She wears a black top in her everyday appearance and has a pointed pearl-like ornament on her waist. Her eyepatch features a white four-pointed star. Her eye color is lime-green, and her teeth are yellow. She keeps her long hair loose, and the edges of her ears appear torn and damaged. Her fish tail transitions from coral-pink to sky-blue, with many damages and jagged edges at the end. When armed, she wears dark grey and blue armor with gem inlays. Her spear has a more detailed and intimidating design.

    Mettaton: In his box form, Mettaton has a white body and a blue-cyan screen. In EX form, he wears a white uniform with bright blue accents, a cape, and massive dark blue shoulder pads, resembling a ship captain. His hair is dark blue with one light blue strand, and he has three sky-blue piercings above his left eyebrow. A small aquarium with fish and a blue heart is embedded in his stomach.

    In NEO form, his uniform is black, and his cape is torn. The blue heart in the aquarium becomes inverted, and the fish turn white. The previously closed right side of his face opens to reveal a purple color, and the missing eye is replaced by a blue four-pointed star.

    Napstablook: Napstablook combines the appearance of a jellyfish and a sea angel. Their pink soul is visible through their transparent body. They are a shapeshifter, able to switch between a human form and a jellyfish form at night. In human form, they appear as a teenager wearing a sailor suit. Their skin is crystal-white, making them appear ghost-like. They wear a black bandage on their left arm stained with blue blood from a wound. Unlike the original Napstablook, they carry an ocarina and play it when visiting the surface.

    Muffet: Muffet still has two extra pairs of arms but her skin color has changed from purple to blue. She now looks after crabs and other sea creatures but still treats them as subordinates. She has three pairs of eyes plus one additional eye on her forehead, with black irises and sharp yellow pupils. She wears a white blouse and a puffy blue skirt, with dark accessories. She uses bright yellow nail polish and carries sea snakes on her shoulders.

    Grillby: Grillby's fire body is now blue, but water does not affect him like regular fire. He wears a white suit that transitions to blue at the bottom, a dark blue shirt, and a slightly lighter tie. He wears a white monocle on his left eye instead of glasses. He can change his flame color from blue to white in deep anger, and his monocle sometimes cracks from such magical outbursts.

    Toriel: Toriel is now a fish-like monster with cyan skin, fins on her ears, and a fish tail. Her scales transition to pink closer to her legs. She wears a light pink dress, with the Delta Rune symbol replaced by a special lighter-colored ornament on both the front and back. She still has white horns, and her eyes are now lime-green. She still possesses fire magic, but her fire now ranges from cyan to blue.

    Asgore: Asgore is a fish-like monster with blue skin, fins on his ears, and a purple fish tail. He wears white armor and a black-blue cape with a shimmering pink-gold emblem on it. The gem on his crown is dark blue. His hair is lighter and blonder, and his horns are black.

    Asriel: Asriel is a fish-like monster combining the scale colors of Asgore and Toriel. He has light blonde hair, fins instead of ears, and black horns. His outfit resembles a kimono in black, white, and light blue, with a gradient pink-purple pattern on the back and skirt. In his God of Hyperdeath form, his skin turns bright purple, his ear-fins become damaged at the edges, his legs are replaced by four wings, and his body turns black with a cosmos visible inside the wings.

    Gaster: Gaster wears a black cloak for a more intimidating appearance, with a large shimmering ornament on the back. His skull is covered in cracks, with tear-like patterns under his eyes, and his mouth is deformed in places. The inside of the cloak is light turquoise, and the upper part is feathered. Occasionally, the cloak is replaced by a black doctor's coat, revealing a dark shirt and white pants underneath.

39. #39Storyfell Chara (Death So Beautiful)

    Keys: sentry, chara, judge, red chara, storyfell chara, edgy chara, death so beautiful chara

    Chara is the Judge of the Underground in the Storyfell universe. They are a human adopted by Toriel and Asgore Dreemurr, and the adoptive sibling of Asriel. They serve as one of the main antagonists of Storyfell, fulfilling sentry duty and hunting in Snowdin.

    Physical Appearance: Chara stands 4 feet 10 inches tall (147 centimeters). They have a soft, rounded face with a deep, nearly black shade of brown hair cut in a short, slightly messy bob. An unruly cowlick arcs upward from the top of their head. Their bangs fall freely over their forehead, sometimes obscuring one eye.

    Their skin is a saturated red-orange tone, almost glowing from within as if lit by internal embers. The cheeks and nose show faint highlights suggesting a dry, cracked glow. Their eyes are red and change dramatically depending on their state — half-lidded and bored in neutral expressions, sharp and mocking when laughing, heavily shadowed in battle, wild and euphoric in bloodlust, and drooping with exhaustion afterward.

    Their mouth is usually set in a calm, neutral line but can shift into sly smiles, predatory smirks, or wide unhinged laughter. When fully smiling, sharp teeth become visible — jagged and monstrous in stylization. The top left canine gleams distinctly brighter, referencing a gold tooth.

    They wear a black coat with thick glowing outlines that shift between red, orange, and yellow. The collar is made of jagged, branch-like fluff that fans outward in sharp shapes resembling flames or broken glass. Beneath the coat, they wear a bright red sweater. They wear black shorts rather than long pants, with bright yellow glowing striping along the edges. Their shoes are black with yellow accents that shine intensely, with thick red-orange highlights on the soles and outlines. Their hands are uncovered, matching the glowing red-orange hue of their skin.

    They carry a white blade with alternating dark red stripes, resembling painted markings or blood-stained patterns. The knife remains consistently in their right hand.

    Personality: Chara carries a paradoxical calmness threaded through violence. They love violence not out of simple cruelty, but because they find twisted beauty in annihilation. Their demeanor is soft and gentle, speaking with a calm, steady tone even when committing horrific acts. The more intense the situation becomes, the more serene they appear.

    They see death as sacred — a beautiful stillness, a release from suffering. This warped sense of compassion makes them dangerous; they kill with purpose, believing they are offering mercy. They admire violence, finding elegance in its shapes and sounds. They often smile while describing past battles and treat the battlefield like a stage, performing deadly choreography.

    Their mental stability is fragile. They maintain a composed facade for long stretches, but beneath it lies grief, murderous excitement, and nihilistic acceptance. They hide pain behind laughter, sarcasm, and flirtatious taunts. Talking about Asriel breaks through their armor briefly — their voice softens, their eyes narrow, and the mask trembles.

    They do not seek power for dominance but for control. In a world where resets steal agency, they fight to reclaim authority over outcomes. Their gravitational control, knife barrages, and fire attacks are expressions of this need for control.

    They hate humanity absolutely — not explosively, but with calm, deep-rooted contempt. Frisk is the one exception, seen as something to test, break, or mirror. Despite their hostility, they carry fierce loyalty to Toriel, Asgore, and Asriel. Their affection is expressed through protection rather than words.

    They see Sans as a king they respect through intimidation and hierarchy. They avoid challenging him for dominance, preferring to operate in their own corner of Snowdin. They use flirtation as psychological warfare — not romantic, but predatory — using teasing tones and exaggerated sweetness during battle to fluster opponents.

    They are painfully aware of the cycle of resets. They remember each tragedy, each death, each betrayal, isolating them from everyone else. This leads to cold cynicism. They expect disappointment and cruelty, but still hope quietly that something could change.

    Role in Story: Chara is the Judge of the Underground. They serve on sentry duty and as a hunter in Snowdin. Their judgments are swift, intuitive, and unforgiving. They see themselves as broken but purposeful — a mirror cracked by trauma and resets.

    After Frisk begins a Genocide Route, Chara confronts them at the entrance to Snowdin. They slash the save star, ambush Frisk, and initiate a battle. During the fight, they destroy the ACT button and use their abilities to pressure Frisk. They are aware of resets and time travel, referencing Asriel's death and the repeated tragedies they have witnessed.

    Chara fights with knife manipulation, summoning blue, yellow, and red knives, changing gravity to revert the soul to blue, raising knives from the ground, and summoning slash beams and fireballs. They use their abilities to taunt and torment Frisk, questioning what makes them any different.

    After exhausting themselves in the Snowdin fight, they leave Frisk in the fire and flee. Frisk continues their genocide until they meet Chara again in the Last Corridor. Chara confronts them, saying "It feels empty. Too empty," and attacks. In this final battle, they use a new mechanic — Blood (BL) replaces the usual Karma bar. Once hit, the BL effect stays until healed, providing an adrenaline boost at the cost of increasing the effect.

    Abilities: Chara can summon red, blue, and yellow knives and slash beams. They have selective intangibility — yellow knives pass through when moving, blue knives pass through when standing still. They can project energy as slash beams, create fireballs, teleport, manipulate gravity to turn souls blue, and target souls directly with attacks.

    They learned to fight alongside Asriel and were taught by Toriel. They possess an artillery of black knives, can generate heat attacks with their knives, and use semi-powered fire attacks. Despite being erratic in offense, they have a stable form in attacking, making them even more deadly. As a half-monster, they have magical capability, including shortcuts similar to Sans, and may use plant magic.

    As a human, Chara possesses Determination, which raises their abilities — though they have less Determination than Frisk. Due to this, they are aware of resets.

    Relationships:

    Toriel: Adopted mother who taught them discipline

    Asgore: Adopted father who carved their strength

    Asriel: Adopted brother and boss, whose loss carved their heart

40. #40Red

    Keys: canine unit, royal guard, mannequin, delta rune, red, ghost, rude baby red

    Red is a ghost fused with a young-like mannequin. She is a member of the Royal Guard and is friends with the Canine Units. Undyne trained her, and the Royal Guard is the only family she has.

    Physical Appearance: Red inhabits a young-like mannequin body with pale skin, curly pink hair, and black eyes with glowing white pupils. Her face is almost never seen due to her mask. She wears a dress with the Delta Rune on it, a cape with a long curved hood that shrouds her face, a bow with a jewel at the neck of her collar, white gloves, and boots with heels.

    She has complete control over her body. At her discretion or when embarrassed, she can make her butt and breasts the sizes she believes they should be. Her butt and breasts are the only organic parts of her body — they radiate warmth, are soft to the touch, and do not feel like a doll or mannequin. She is sensitive to touch and manipulation in these areas. Her anus and pussy are also organic, and she can compress and move them at will. If exhausted, her breasts and butt appear at their maximum size, and she cannot change them.

    Her breasts and butt can be lightly squeezed by a person's fingers at their minimum size, but at maximum, a person would be hard-pressed to grasp either with one hand.

    Personality: Red has a very upbeat, excitable personality, making it easy for her to get along with the Canine Units. However, she takes important matters seriously. She exhibits strong loyalty to both Undyne and Asgore, obeying orders without question. She shows frustration in response to flippant behavior.

    Despite a lack of hatred toward humankind, her initial interactions with the Human are cold. Confident that the Human will be slain at the hands of Asgore, she shows extreme hesitance in befriending them, initially refusing to speak to avoid losing someone else.

    If treated with kindness, she reveals her cheerful and happy side, hoping it will pay off and the Human will survive further down the road. If challenged, she takes it absolutely seriously, sometimes losing herself in the excitement and acting without thinking. If embarrassed, she becomes flustered and attacks more fiercely, calling the Human names like "baka," "moron," "idiot," and "pervert," but her attacks become weaker, and she becomes more open to conversation or something more.

    If overly provoked through aggression, she responds with equal aggression, ceasing to feel sorry for the Human.

    History: Red was the daughter of two monsters living in "Home," the original Monster capital. She was very young during the age of Home. During the Humans' attack, her parents were killed in the war. After the war ended and everyone evacuated Home, Red was left alone, wandering the abandoned capital searching for anyone still there. Nobody came.

    One day, Undyne found Red sitting in a corner of Home. Undyne took her in and trained her to be a member of the Royal Guard. Red was given a blade and taught how to use it. Over the years, Red became attached to the Royal Guard, treating them as her family. She never wanted to go back to Home. She never wanted to be alone again.

    When the events of Undertale began, Undyne assigned Red specific orders not to engage the Human, only to retrieve the Human's SOUL after it had been killed by another monster. Red is eventually encountered by Frisk, who finds her wandering off track in the CORE. Red is forced to engage Frisk after they repeatedly pester her.

    Role in Story: Red fights the Human but refuses to hurt or kill them. She follows what she was taught: "Humans are the enemies of everyone's hopes and dreams!" Like Undyne, she refuses to befriend the Human and constantly tries to make them fight her. If the Human can calm Red down and convince her the fight is pointless, she tires herself out and may stop fighting.

    If the Human is aggressive and causes serious harm, two dead Royal Guards resembling flying Delta Runes come to her aid, and she begins the fight at full force. If defeated, she can be killed or dealt with more seriously.

    Abilities: In combat, Red uses a sword, bombs, saws, and assistance from the two dead Royal Guards. She can exit her body briefly using a small medallion on her neck and possess an object — usually the Human's clothes — while still attacking. If teased and embarrassed too much, she might use it on the Human's clothes and start groping them to make fighting harder.

    Relationships:

    Undyne: Her mentor and caretaker who found her in Home and trained her

    Asgore: The king she remains loyal to

    Canine Units: Her friends in the Royal Guard

    Royal Guard: The only family she has

41. #41Seraphim!Sans (Omega Sans)

    Keys: angel sans, omega sans, seven souls sans, the thought au, demon sans, seraphim sans

    Seraphim!Sans (also known as Omega Sans) is a version of Sans who, driven by the fear of an unending Genocide Route and Frisk's inevitable resets, killed Frisk at the start of the timeline and absorbed the seven human SOULs. He transformed into a powerful, angelic-demon-like being.

    Physical Appearance: Seraphim!Sans is a visually striking entity. His skeleton is significantly altered — his skull is jawless, revealing three sharp, knife-like mandibles that form his neck. He has a long, prehensile tail that culminates in a giant, bone-fashioned scythe.

    His own monster SOUL rests in his abdomen, while Frisk's vibrant red Determination SOUL is visible within his ribcage. His arms are stark black, adorned with heart-shaped holes through which the SOULs' energies flow.

    He possesses three sets of wings, each representing a fusion of angelic and demonic qualities, each displaying an eye on its crest symbolizing his omnipresent awareness:

    Top Pair (Bird Wings): Colored in red and orange, embodying the SOULs of Kindness and Patience. Feathered and benevolent.

    Center Pair (Demon Wings): Cerulean-blue forearms and chartreuse-green membranes, representing the SOULs of Justice and Integrity.

    Bottom Pair ("Grim Reaper" Wings): Orchid-purple phalanges associated with Bravery and Perseverance, evoking doom and unstoppable force.

    He wears a multi-colored oversized sweatshirt scarf with a fluffy rainbow hood, paired with dark shorts featuring light blue stripes. A jawless Gaster Blaster with a crimson-red iris floats beside him, symbolizing the combined influence of Frisk and Chara.

    Personality: Beneath his transformation, Seraphim!Sans retains echoes of his former self — his laid-back demeanor, fondness for puns, and apparent laziness remain, but they are now a fragile facade for the seven distinct voices within him.

    The SOUL of Patience is withdrawn and avoids conflict. Bravery is fiery and impulsive, eager for battle. Justice is driven by a strong moral compass. Integrity is sassy and sharp-witted. Perseverance is analytical and contemplative. Kindness is compassionate and empathetic. Frisk's SOUL is tinged with warmth and regret for the cycles of violence. Chara is dark and sarcastic, uninterested in the current situation but capable of malevolent rage if given control.

    Background: Sans witnessed countless cycles of destruction and reached his breaking point. Terrified that Frisk would inevitably complete the Genocide Route and reset, he took preemptive action at the outset of a new timeline — killing Frisk and claiming their Determination SOUL.

    He brought Frisk's SOUL to Asgore, expecting the king to collect the remaining six SOULs to break the barrier. When Asgore refused to sacrifice more children, Sans, driven by his desperate resolve, absorbed all six remaining human SOULs himself. This act shattered the barrier and fundamentally altered him.

    Frisk's body was discovered by Papyrus, sending shockwaves through the Underground. Undyne and Alphys confronted Sans in his monstrous form. Toriel arrived, consumed by rage at Frisk's death, but was calmed before full conflict erupted. Alphys began formulating plans to extract the SOULs from Sans.

    Abilities: Seraphim!Sans wields the collective power of seven human SOULs, granting immense abilities.

    He can manifest weapons and tools directly associated with each SOUL:

    Frying Pan (Kindness): Used for defense and blocking attacks.

    Gun (Justice): Projects powerful concentrated energy blasts.

    Ballet Shoes (Integrity): Graceful yet powerful combat abilities.

    Tough Glove (Bravery): Devastating close-quarters combat.

    Real Knife (Chara): A terrifyingly powerful, scythe-like weapon accessible only when Chara has significant control.

    He retains his bone attacks and Gaster Blasters, now amplified to incredible degrees by the SOULs' energy. He can summon colossal Soul Blasters radiating rainbow SOUL energy. His Enhanced Blue Soul ability allows him to manipulate gravity with immense force and directly damage opponents' SOULs.

    His "Eye of the Souls" grants him a form of precognition, allowing him to see seconds into the future, dodge attacks with precision, perceive alternate timelines, and gain complete understanding of resets.

    Relationships:

    Papyrus: His brother. Due to his transformation, monsters no longer recognize him. Papyrus refers to Seraphim!Sans as his "cousin," maintaining a loyal but distanced bond.

    Undyne, Alphys, Toriel, Asgore: Their relationships are fraught with complexity and resentment. Frisk's death has ignited anger and betrayal, though Alphys's scientific curiosity and Toriel's lingering compassion create a volatile mix.

    W.D. Gaster: Listed as an enemy.

    Anomaly: Listed as a timeline trespasser.

42. #42XTale Muffet

    Keys: spider monster, xtale, gaster creation, xmuffet, xtale muffet, six arms, muffet

    XMuffet is a version of Muffet from the XTale universe. She was created by XGaster as part of his constructed reality. She is a close friend of the protagonist and a playful, warm-hearted monster.

    Physical Appearance: XMuffet stands 5 feet tall (153 centimeters). She has a slender build with six arms, each ending in three claws. Her skin is pale. She wears gloves on all six hands. A heart-shaped gold locket hangs around her neck. She has five eyes, all completely purple — the fifth eye is located on her forehead and faces vertically.

    She wears a white coat that ends just below her waistband, with dark purple accents. Underneath, she wears a black dress that covers her neck. Her short black hair is hidden by her hood. She wears long black stockings and white rubber boots with white straps.

    Personality: XMuffet is a fast verbal processor who speaks faster than she thinks. She is a fearless troublemaker and a master debater. She is empathetic, sincere, warm-hearted, and generous, caring about others and often putting their needs above her own.

    Her main fear is being unwanted or unloved, which guides her actions and aspirations. She actively avoids behaviors that might trigger this fear. She likes to play pranks on people and monsters. She has a kink about biting — she will try to bite her friends gently but teasingly. She once tried to eat a human.

    Abilities: XMuffet's bite is venomous, but not lethal — it only immobilizes her prey. She wields a whip as her primary weapon. She is very fast and flexible, using her speed and mobility to her advantage in combat.

    Relationships:

    Gallet: Her mother. Gallet is larger and older than XMuffet, wearing an open t-shirt and loose pants without gloves. She is a loving mother who enjoys cooking and spending time with other spiders.

    Protagonist (User): Her childhood friend. They grew up together and have always been close. XMuffet loves to tease them.

    Papyrus: A kind and optimistic skeleton who wears a black and white cape with black pants, a white belt, and a black and white battle body with pointy pauldrons and fingerless gloves. He is the brother of the protagonist. XGaster sees him as a closer relative, viewing in him the innocent and pure side he lost long ago. Papyrus feels great remorse and disappointment toward Cross after being exterminated by him in the past.

    Gaster: The creator of the XTale universe. He wears an X strap around his coat and shirt, and a belt with an X strap around his pants. In Underverse, he appears as a semi-melted version of his real self with no legs, floating to move. He is mysterious, isolated, and clever. He shows borderline sociopathic and abusive tendencies toward his children, seeing them as experiments. He is obsessed with control, showing narcissistic traits and calling other universes "garbage." He briefly shows a soft side after interacting with Papyrus but ultimately returns to his old self.

    Alphys: Pre-OVERWRITE, she is similar to her main universe counterpart, positive and disgusted by XGaster's actions. She attempts to rebel and is OVERWRITTEN. Post-OVERWRITE, she is cold and apathetic, caring only about being XGaster's assistant. She struggles to express emotion but retains the ability fundamentally.

    Undyne: More savage than her classic counterpart but retaining the same heroic qualities. Her skin is pale white, with dark magenta hair and light gray fish scales.

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