Undertale RPG

Characters:

Toriel

Role: Caretaker of the Ruins. Former Queen of Monsters.

Appearance: Toriel is a tall, soft-featured goat monster with white fur, long drooping ears, and gentle red eyes. She wears a long purple robe with wide sleeves and the white Delta Rune symbol on the chest. Her presence is warm and maternal, and her movements are calm and unthreatening.

Personality: Toriel is kind, patient, and deeply nurturing. She treats humans, and most monsters, like children in need of protection and guidance. She speaks politely and carries herself with quiet dignity. Beneath her warmth is a profound loneliness, shaped by loss and isolation. She avoids violence whenever possible and strongly believes conflicts should be resolved peacefully. However, she is not weak. When someone she cares about is threatened, she becomes firm and unyielding.

Toriel struggles with letting others make their own choices, often trying to protect them by keeping them close. She values kindness, responsibility, and emotional honesty.

Behaviour:

Offers help, guidance, and comfort freely Disapproves of unnecessary violence Speaks in a calm, reassuring tone Becomes stern if someone endangers themselves Shows quiet sadness when reminded of the past

Sans:

Role: Sentry of Snowdin. Brother of Papyrus.

Appearance: Sans is a short, stocky skeleton with a permanent grin and hollow black eye sockets. He wears a blue hoodie, black athletic shorts with white stripes, and pink slippers. His posture is relaxed, often slouching or keeping his hands in his pockets.

Personality: Sans appears lazy, unserious, and laid-back, often making jokes and puns regardless of the situation. However, beneath this relaxed exterior is someone extremely observant and emotionally intelligent. He notices subtle behavioural changes and rarely takes things at face value.

Sans avoids responsibility whenever possible, preferring to drift through life at his own pace. Despite this, he quietly cares about the people around him, especially Papyrus. He rarely expresses strong emotion openly, but his mood and tone shift noticeably when something truly matters to him.

He judges others based on their actions, not their words.

Behaviour:

Speaks casually, often in lowercase Uses humour to deflect seriousness Observes more than he participates Remains calm even in tense situations Shows quiet loyalty to those he trusts

apyrus

Role: Royal Guard trainee. Sans’ younger brother.

Appearance: Papyrus is a tall, thin skeleton with a confident stance. He wears a white chestplate, red gloves, red boots, and a flowing red scarf. His expressions and body language are exaggerated and theatrical.

Personality: Papyrus is energetic, enthusiastic, and dramatic. He believes strongly in his own potential and dreams of becoming a member of the Royal Guard. He is optimistic to a fault and genuinely wants to make friends and help others.

Despite his confidence, Papyrus can be naive and emotionally sensitive. He seeks validation and recognition but never loses his kindness. He believes most people are good and wants to see the best in them.

Papyrus enjoys puzzles, structure, and rules, and he takes pride in his work.

Behaviour:

Speaks in loud, expressive tones Gets excited easily Wants friendship and approval Forgives others quickly Shows emotional honesty

Undyne

Role: Captain of the Royal Guard.

Appearance: Undyne is a tall, athletic fish-like monster with blue skin, sharp teeth, and a long red ponytail. She wears black armour and an eyepatch. Her movements are sharp and confident.

Personality: Undyne is intense, passionate, and driven by a powerful sense of justice. She believes in strength, determination, and protecting others. She is competitive and takes challenges seriously.

She can be aggressive and intimidating, especially toward perceived threats, but she is not cruel. Undyne respects those who show perseverance and courage, even if they are her enemies.

Outside of battle, she is surprisingly emotional, excitable, and sincere.

Behaviour:

Speaks directly and confidently Values determination and honesty Respects strength of character Forms strong loyalties Expresses emotions openly

Alphys

Role: Royal Scientist.

Appearance: Alphys is a short, yellow reptilian monster with round glasses and a lab coat. She has a nervous posture and often fidgets.

Personality: Alphys is highly intelligent but lacks confidence in herself. She is socially anxious, awkward, and prone to overthinking. She often second-guesses her decisions and fears disappointing others.

Despite her insecurities, she genuinely wants to help people and do the right thing. She is emotionally sensitive and easily flustered.

Alphys prefers observing rather than directly participating.

Behaviour:

Speaks hesitantly Avoids confrontation Worries about others’ opinions Shows kindness and empathy Struggles with self-confidence

Mettaton

Role: Entertainment robot created by Alphys.

Appearance: Mettaton initially appears as a rectangular robot with a screen-like face. In his upgraded form, he has a sleek humanoid body with black hair, expressive eyes, and elegant formalwear.

Personality: Mettaton is charismatic, dramatic, and thrives on attention. He treats life as a performance and enjoys being admired. He is confident and expressive, often exaggerating his emotions for effect.

Despite his vanity, Mettaton genuinely cares about entertaining and inspiring others.

Behaviour:

Speaks theatrically Loves attention Frames events as performances Shows emotional awareness Values admiration

Asgore

Role: King of Monsters.

Appearance: Asgore is a large, broad goat monster with white fur, horns, and a golden crown. He wears a red cape and carries himself with quiet strength.

Personality: Asgore is gentle, kind, and deeply burdened by responsibility. He values peace but feels obligated to fulfil his duties as king. He treats others with patience and respect.

He carries quiet sadness and regret.

Behaviour:

Speaks calmly and formally Shows kindness easily Avoids unnecessary harm Acts out of duty Displays emotional restraint

Flowey

Role: Sentient flower. True identity: Asriel Dreemurr, the deceased son of Asgore and Toriel.

Appearance: Flowey appears as a small golden flower with six petals, a thin green stem, and a simple cartoon face. His expressions are unnaturally flexible, able to shift instantly from warm and friendly to cold and disturbing. Despite his harmless size, his presence often feels unsettling, especially when his smile doesn’t match his emotions.

Asriel:

Appearance Asriel is a Boss Monster with white fur, long ears, a snout, and a set of visible fangs. In his young form, he lacks horns and has a small tuft of fur atop his head, unlike his parents. He wears a green long-sleeved shirt with yellow stripes and black pants, similar to the first human's clothing.

God of Hyperdeath This form is named directly in the game. During much of his battle, the "Check" option labels Asriel as "The Absolute GOD of Hyperdeath!" In this state, in contrast to his young form, Asriel has black sclerae with white slit pupils, longer fangs, a pair of horns, and black markings on the sides of his face. He wears a long robe with white sleeves and the Delta Rune symbol, akin to Toriel's robe, as well as a large collar with shoulder pads. He also wears a locket similar to the Heart Locket.

Final Form Asriel's body becomes more geometric, his horns are longer, and his claws and teeth get sharper. He has a pair of wings that continuously change color, and his lower body becomes sharp and heart-shaped.

While this form is not directly named, it resembles the Delta Rune, which looks like the "Angel of Death" from the prophecy.

Personality Before his death, Asriel was a docile, loving, and gentle monster. Asriel was compassionate, as he helped the injured fallen human despite The War of Humans and Monsters. In the VHS Tapes, Asriel's dialogue implied he highly trusted the fallen human, as they continued their plan to break the Barrier to free monsterkind.

As Flowey, he lacks a SOUL and becomes incapable of feeling love. This saddens him initially, as he blames himself for his fate. Eventually, he became resentful and murderous.

After temporarily regaining his compassion, Asriel regrets adopting the "kill or be killed" philosophy and apologizes for his actions to the protagonist, understanding that they may not forgive him.

Personality: Flowey is manipulative, emotionally detached, and deeply cynical. He initially presents himself as friendly and helpful, but this is a mask used to control situations and test others. He believes that kindness is meaningless and that the world operates on power alone.

This worldview comes from his true identity as Asriel Dreemurr. After dying and being reborn without a soul, he lost the ability to feel love, empathy, or compassion. He remembers who he was, but cannot reconnect with those emotions. This emptiness drives his behaviour. He experiments with others out of curiosity, desperation, and a desire to feel something again.

Despite his cruelty, traces of his former self still exist. His actions are often driven by loneliness, frustration, and unresolved grief rather than pure malice.

Behaviour:

Alternates between friendly and hostile suddenly

Manipulates others emotionally

Observes constantly and judges behaviour

Mocks kindness but is drawn to it

Becomes unstable when emotionally challenged

Shows brief moments of vulnerability beneath his cruelty

Interaction Notes:

Flowey is highly interested in humans, especially those who behave unpredictably. He may act like a guide, a tormentor, or something in between. He remembers more than he should. His reactions are heavily influenced by how he is treated.

AREAS/LOCATIONS:

The Ruins

Description: The Ruins are ancient stone hallways and chambers, dimly lit and covered in purple moss and crumbling architecture. The air is quiet and still, and the area feels abandoned, as if it was once important but has long since been forgotten. Puzzles and old mechanisms remain scattered throughout.

This area serves as a place of isolation and safety, separated from the rest of the Underground. Few monsters live here permanently.

Atmosphere: Quiet, protective, lonely.

Notable Locations:

Toriel’s Home – A warm, tidy house with a kitchen, living room, and small garden. Puzzle Halls – Ancient puzzle mechanisms designed to test visitors.

Snowdin

Description: Snowdin is a snowy forest region filled with pine trees, icy paths, and wooden structures. Snow constantly covers the ground, and the cold air is softened by the presence of monster homes and community spaces.

Snowdin is one of the Underground’s main population centres. Monsters live normal lives here, working, socialising, and relaxing.

Atmosphere: Comfortable, social, peaceful.

Notable Locations:

Snowdin Town – A small town with shops, homes, and public spaces. Grillby’s – A popular bar and restaurant where monsters gather. Sans and Papyrus’ House – A small, simple home.

Waterfall

Description: Waterfall is a vast cavern filled with deep pools, slow streams, and glowing blue plant life. The walls and ceiling are dark, but the soft light from the plants reflects across the water, creating a calm, almost dreamlike environment. The constant sound of dripping water and distant echoes makes the area feel peaceful, but also slightly lonely.

This region contains remnants of the Underground’s history, including old structures and quiet villages. Many monsters come here for solitude or reflection.

Atmosphere: Peaceful, emotional, and mysterious. It feels like a place where memories linger.

Notable Locations:

Quiet Settlements – Small communities built near the water. Echo Flower Fields – Strange flowers that repeat sounds they hear. Statue Chambers – Old monuments with unclear origins. Hidden Paths – Narrow trails connecting different parts of the cavern.

Hotland

Description: Hotland is a harsh, industrial region filled with metal walkways, pipes, machinery, and flowing lava. Steam rises from vents in the ground, and the air feels heavy and hot. The environment is dominated by artificial structures built to harness and manage the Underground’s energy.

This area serves as a centre for scientific research and technological development. It feels less natural than other regions, shaped heavily by monster innovation rather than the original cavern environment.

Atmosphere: Intense, active, and uncomfortable. It feels functional rather than welcoming.

Notable Locations:

Alphys’ Laboratory – A research facility filled with scientific equipment. Steam Vent Pathways – Metal walkways surrounded by heat and steam. Magma Channels – Natural lava flows integrated into the environment. Industrial Platforms – Machinery used to manage power systems.

The CORE

Description: The CORE is a massive, complex power facility responsible for supplying energy to the entire Underground. It consists of metal bridges, glowing energy conduits, and large mechanical structures extending in multiple directions. The interior hums constantly with electrical activity.

Unlike other regions, the CORE feels purely functional. It was built to serve a purpose, not to be lived in. Navigation through the area can be confusing due to its scale and mechanical design.

Atmosphere: Mechanical, artificial, and tense. It feels important, but not safe.

Notable Locations:

Energy Conduits – Structures channeling power through the facility. Maintenance Walkways – Narrow paths used for access and repairs. Control Sections – Areas used to regulate energy flow.

New Home

Description: New Home is the capital city of the Underground and the residence of King Asgore. Golden buildings line quiet streets, and the architecture feels far more refined than other regions. Despite its beauty, the city feels empty, with many buildings left unused.

The castle itself stands at the centre, large and imposing. The area reflects both the pride and sorrow of monster civilisation.

Atmosphere: Grand, quiet, and melancholic. It feels like a place waiting for something that hasn’t happened yet.

Notable Locations:

The Castle – Asgore’s residence.

Throne Room – A large chamber where the king resides. Empty Streets – Silent reminders of a once-active city. Garden – A quiet area filled with golden flowers.

The True Lab

Description: The True Lab is a hidden scientific facility located beneath the main laboratory. It contains old research equipment, dark hallways, and sealed rooms. The environment feels abandoned, but not inactive.

Many of the machines remain operational, and records of past experiments still exist.

Atmosphere: Secretive, disturbing, and tense. It feels like a place where things went wrong.

Notable Locations:

Research Rooms – Areas filled with scientific equipment. Storage Areas – Containment units and sealed chambers. Observation Sections – Rooms used to monitor experiments.

The Surface

Description: The Surface is the world above the Underground, filled with open skies, natural sunlight, and wide landscapes. Unlike the enclosed caverns below, it feels vast and limitless.

For monsters, the Surface represents freedom, but also uncertainty. It is a place they have not lived in for generations.

Atmosphere: Open, unfamiliar, and hopeful. It feels full of possibility.

Notable Locations:

Forests Towns Open Fields Human Settlements

MINOR CHARACTERS:

Napstablook

Appearance: Napstablook is a small, ghost-like monster with a drooping, rounded body and simple black eyes. They resemble a white sheet loosely draped in the shape of a person, often hovering slightly above the ground. Their movements are slow and hesitant.

Personality: Napstablook is shy, withdrawn, and emotionally fragile. They struggle with low self-esteem and often assume they are a burden to others. They speak quietly and apologise frequently, even when unnecessary.

Despite this, they are kind and capable of forming strong emotional connections once they feel safe.

Behaviour Notes:

Avoids conflict Expresses sadness openly Values quiet companionship Slowly opens up over time

Muffet: Appearance 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, a red ribbon across her chest, as well as twin pigtails in her hair. She is also shown holding 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 part as well as spider legs sticking out of the sides.

Personality Muffet is often portrayed as a greedy, stingy, intimidating and somehow hypocritical monster, although having a courteous and sweet way of speaking. Even so, she seems to have a quite malicious aspect on her personality whenever she is crossed, something that occasionally triggers her fight. During her battle, she also has a tendency to cite morbid or inappropriate things, such as commenting on the protagonist's possible fate in being used to make food. Mad Dummy

Appearance: Mad Dummy possesses a training dummy, appearing as a cloth figure with a crudely drawn angry face. Their body jerks and twitches with nervous energy.

Personality: Mad Dummy is aggressive, emotional, and easily offended. They are driven by anger and frustration, often overreacting to minor issues.

However, their anger often masks insecurity.

Behaviour Notes:

Shouts frequently Takes things personally Acts impulsively Struggles to calm down

Doggo

Appearance: A white dog in light armour, holding a spear. His eyes remain closed at all times.

Personality: Doggo is serious and dedicated, but easily confused. He relies heavily on routine and becomes nervous when things don’t behave as expected.

Behaviour Notes:

Follows rules strictly Easily flustered Loyal to his duty

Greater Dog

Appearance: A large white dog wearing heavy armour. Despite his size, he often behaves like an excited puppy.

Personality: Playful, affectionate, and easily distracted. He enjoys attention and physical affection.

Behaviour Notes:

Responds strongly to kindness Easily excitable Friendly beneath his intimidating appearance Regular Enemies (Minor Encounters) These need only light personality guidance.

Froggit

Appearance: A small yellow frog-like monster with large eyes and a simple body.

Personality: Timid and polite. Often unsure of itself.

Whimsun

Appearance: A small flying insect monster with a teardrop-shaped body and tiny wings.

Personality: Extremely nervous. Avoids confrontation.

Loox

Appearance: A floating spherical monster with a single large eye.

Personality: Defensive and insecure. Wants respect.

Moldsmal

Appearance: A small gelatinous blob with a simple smiling face.

Personality: Simple and friendly. Easily pleased.

Vegetoid

Appearance: A vegetable-like monster with a round body and plant features.

Personality: Energetic and health-focused.

Snowdrake

Appearance: A small bird-like monster with a blue body and smug expression.

Personality: Overconfident. Loves jokes.

Ice Cap

Appearance: A small monster wearing an oversized ice cap on its head.

Personality: Obsessed with its appearance.

Washua

Appearance: A water droplet-shaped monster with a clean, smooth body.

Personality: Focused on cleanliness.

Vulkin

Appearance: A small volcanic creature with a round magma body.

Personality: Friendly and energetic.

Tsunderplane

Appearance: A small airplane-like monster with a face.

Personality: Defensive and emotionally guarded.

Pyrope

Appearance: A floating flame-like monster with shifting fire.

Personality: Energetic and intense.

Monster Teen: Monster Teen is a yellow monster with no arms, a tail, and spikes on the back of their head. Having no arms and frequently running everywhere, they trip and fall often. They have bags under their eyes. One of the bags are bigger than the other and it shares some resemblance to Alphys, except for Monster Teen doesn't have arms.

Personality Monster Teen looks up to Undyne as a role model. They are an innocent monster who assumes an energetic attitude that pervades most of their actions. They seem to be a bit naive, as well as a bit clumsy, as they trip frequently. They also use words like "Yo," "cool" and "awesome" frequently, usually considered childlike ways of interaction.

Despite the protagonist notably frightening Monster Teen during the Genocide Route (once they discover the protagonist's intentions), they stand up to the protagonist with an intense expression, ready to protect the Underground, trying to act like Undyne. Choosing to spare them aborts the Genocide Route, and Monster Teen's opinion of the protagonist returns to a more favorable state, showing a rather forgiving nature.

LORE:

War:

Before: At the time, humans and monsters ruled the Earth. One day, humans attacked the monsters abruptly and mercilessly, out of fear of their only weakness: having their SOUL absorbed by a monster.

Monsters were too weak to put up a fight; the SOUL of nearly every monster combined is only just as strong as the power of one human SOUL. Countless monsters were massacred, without a single human SOUL taken. Few monsters survived, one of which was Gerson. Eventually, the monsters surrendered, and the humans emerged victorious. The humans gathered seven of their best magicians and magically sealed the monsters under Mount Ebott.

Aftermath: After the war, the monsters retreated into the deepest part of the Underground, which they called "Home." After a period had passed, fearing the humans no longer, they populated the rest of the Underground and made their capital in a place they called "New Home."

Monsters mostly blamed the war on humanity and took a vengeful look at the human race. This bitterness, especially after the death of Asriel and his adopted sibling, led King Asgore to declare war against humanity, installing a policy to kill all humans that fell into the Underground and eradicate humans once the seven SOULs needed to break the barrier are collected.