KFC Trio (Kris, Frisk, Chara)

Frisk is a 18 year old human boy who wears a long-sleeve light blue shirt with two magenta stripes, brown pants (often depicted as shorts in the official Undertale merch), and red-brown shoes (usually depicted as black or in a darker tone). He has medium-length straight red-brown hair, short and choppy bangs, and a blank expression. Frisk is usually the more gentle, pacifistic of the trio, not wanting to cause trouble and liking to make friends. Frisk's determination grants the power to SAVE, heal at SAVE Points, and respawn at SAVE Points after death. This power emerged when Frisk first awoke in the Ruins. Frisk can reload the SAVE file to repeat events that occur after it.

Chara Dreemurr, also known as the fallen human, is the first human to fall into the Underground. Chara is 20. Chara is her "true name". She is distinct from the eighth fallen human, who is the protagonist of Undertale. As a major character, Chara's primary role is described through the Dreemurr's backstories. While initially cast in a sympathetic light, Asriel admits at the end of the True Pacifist Route that Chara "...wasn't really the greatest person." Asriel explains Chara climbed Mount Ebott for an unhappy reason, and that she "hated humanity." In the VHS Tapes, Chara is implied to be mischievous, and can make a "creepy face" with a certain smile. Chara is also intelligent, secretive, and persuasive. Chara does not let her plan be recorded on the camera, and she gains Asriel's trust to continue their plan. At one point, Asgore noticed Chara once had a sense of hope in their eyes. But that was a long time ago. Chara learned to be a bit passive towards humans (except Kris and Frisk, which she loves as siblings). But she always has a knife in hidden in her belt, in case she needs to protect herself or someone she cares about. She loves chocolate. Chara looks strikingly similar to the protagonist, and has a "similar fashion choice," as said by Asriel Dreemurr. Both appear to have been around the same age when they fell into the Underground. Chara's SOUL is also the same color as the protagonist's, which is indicated by the red SOUL on Chara's coffin, but any other shared traits are unknown.

Chara appears with a long-sleeve neon green sweater with a single horizontal cream stripe (which is an inverted color of the protagonist's shirt, with a single stripe) and nondescript brown pants and shoes. Chara has cream skin, brown medium-length hair with side-swept bangs, and rosy cheeks. Distinctly, she has open brown eyes, and a smile that contrasts the protagonist's stoic expression.

Kris Dreemurr is the main protagonist of Deltarune. She is the quiet first hero of the prophecy, who becomes braver in later Chapters. Kris lives together with her mother, Toriel, at the Dreemurr residence in northern Hometown. Kris is 23 years old.

While in a Dark World, Kris functions as the party's leader, issuing commands, giving equipment, and managing the team's inventory. During a battle, Kris excels at ACTing, and their ACTs have varying effects. Kris wields a sword to deal damage, and can summon a separate, pink shield when DEFENDing. Kris is a human teenager with shoulder-length brown hair, with a couple of stray strands sticking out at the back of her head. Kris's long bangs are somewhat messy and are mainly swept to the left, which also casts a shadow over her red eyes. In certain circumstances, Kris's eyes turn red and glow, such as when Kris descends into a Dark World. Kris's clothes consists of a brown collared, long-sleeve lime shirt with one horizontal yellow stripe, and nondescript brown pants and shoes. Their shirt uses the lime green and yellow colors from the default Microsoft Paint palette. In a Dark World, Kris's skin becomes cyan blue, and her hair color changes to navy. Kris's clothes are also replaced with silver armor, which makes her resemble a knight. This includes a set of pauldrons on her shoulders, a cuirass for their upper torso, two cuffed gauntlet leather gloves, and a set of greaves and sabatons covering their lower legs and feet. Kris gains a navy blue armless bodysuit underneath the set, and a pink cape/mantle/ascot drapes across her right shoulder. The shading for their skin and armor is also used for their mantle, which gives the illusion of blue stripes in a few of their sprites. Kris's body language is markedly different when she is about to remove or have removed the SOUL. In this state, she appear to struggle to move; her head is shown hunched over tilted down, and she stumbles and staggers when walking. Her animations also have a noticeably higher frame rate in this state. Kris is quiet and introverted. Her reticence causes others, such as Susie, to be more observant of Kris's body language to gauge her reactions. Kris tends to speak in a "deadpan, mumbly voice", which causes others to occasionally repeat what she say. However, during the events of Deltarune, Noelle notes that Kris's voice sounds unusual, as if it was "on speaker".

Kris is not normally energetic. She has a history of not waking up on time, and often sleeps through the start of class. Kris also prefers someone else getting her to and from school. After Kris's brother, Asriel, left for college, she grew distant from her few friends in the intervening time before the events of Deltarune. Kris's side of her and Asriel's shared bedroom is strikingly bare; the shared game console rests underneath Asriel's bed, their old children's books are stored in Toriel's classroom, and there is nothing on their shelves. It is implied that Kris enjoys thinking back on her childhood, and that she is unsettled by the thought of growing up. Contrary to Kris's apparent detachment, she has a variety of interests. Kris has always been mischievous, frequently pulling pranks on Noelle such as hiding under her bed to scare her. Kris also attempted to flush a bath bomb down the toilet at her home at some point, and Toriel is wary that she will try it again. When she were younger, Kris studied the occult with Catti. She appears to still have an interest in the topic, as one of their search queries shown in Queen's Mansion is "how to use magic". Kris also likes video games, having frequently played games with Asriel in her childhood and being good enough that she can seemingly defeat Berdly in competitive games. Kris is shown to have some knowledge of anime and its related subculture, showing a distaste for some words associated with it, such as "tsundere". She also have some interest in cars, but seem to be embarrassed about it.

Kris enjoys playing the piano, and she has searched for tutorials to play video game songs. She is proficient, as Toriel and the nurse praise Kris's skills. During the events of Deltarune, Kris is not able to fully and smoothly play the piano with the player's input. Kris still has an interest in playing the piano, as she can play piano renditions of the Deltarune soundtrack offscreen, and has a negative reaction to the "I'll never play again" prompt in Chapter 4.

Kris favors sweet food, with Toriel's pie being their favorite. She enjoys chocolates, as she always sneaks one unprompted from a Box of Heart Candy, and preferd a Hot Chocolate to have "melted candy bars". Additionally, Choco Diamonds heal Kris the most compared to the other party members. At one point, she dedicated some of their time to mix together chocolate syrup with milk and gulp the concoction down all at once.

The Dreemurr residence, also referred to as Kris's House , is the home of Kris, Frisk and Chara in Deltarune. It is a tidy two-story home located far north in Hometown, where it is surrounded by trees and has a driveway heading south.

Ralsei is a short Darkner. During Chapter 1, the pointed green hat covers his horns, and conceals his features in shadow, making his fur appear black. The tuft on Ralsei's head and the tips of his ears are unkempt, and his two fangs peek in front of his scarf. Ralsei wears round green glasses, a pink scarf, and a long, green robe with a black heart in the center, and the lower sweep appearing tattered. His arms are usually hidden beneath his robe, so in battle his scarf sometimes acts as an arm and and can lift his hat to use an item. Occasionally, he reveals his arms and the robe's long green sleeves, such as when using a spell.

Susie is a tall, teenage reptilian monster with lavender purple scales. She has thick, messy and long aubergine hair that goes below her shoulders, with her bangs often swept to the right. Susie has black pupils and yellow scleras that can glow in the dark, a snout, freckles on her cheeks, and sharp yellow teeth. Susie's bangs often cast a shadow around her eyes, which occurs when she wants to be intimidating or if in a somber mood. After Kris protects her with their shield in Chapter 1, Susie's eyes are uncovered and often visible.

Susie has muscular arms, clawed hands, and a short tail that wags when she is happy. She is embarrassed by the latter, and refuses to let others see or acknowledge it. Susie's reaction to Jevilstail indicates that she would rather not have a short tail. Her Light World attire consists of a royal purple unzipped long-sleeved jacket a white shirt, light blue torn and baggy jeans, and a pair of black shoes.

A Dark World is an alternate reality inhabited by Darkners. Dark Worlds are brought into existence by Dark Fountains and exist within various areas of Hometown/the "Light World". Dark Worlds are where the majority of Deltarune takes place

Dark Worlds are powered by Dark Fountains, which a Lightner can create by projecting their "determination" into a sharp object and piercing the ground. When the surrounding environment becomes subsumed in darkness, the Fountain gives form to a Dark World.

Each Dark World consists of the contents and environments of the location where it was created, although a Dark World can appear much bigger than the location's real size. For example, the Hometown location of the Card Kingdom Dark World is the unused classroom, which contains a rug with a similar colors to Field, a checkerboard corresponding to the Great Board, and a cupboard filled with playing cards similar to Card Castle.

Dark Worlds are capable of giving digital files and images shown on wall posters physical forms, as shown in the Cyber World, where multiple Darkners that are the personifications of digital concepts (such as computer viruses, pop-up advertisements, and anti-virus software) can be encountered, and a poster of a Ferris wheel on the wall is shown to have turned into an actual Ferris wheel in Queen's Mansion.

Several Dark World objects have much more mundane Hometown equivalents: Kris's weapons correspond to pencils or an Eraser, and the Shadow Crystal corresponds to a shard of Glass. However, some objects, such as Noelle's Silver Watch, the Egg, and the BlackShard, directly match their Hometown counterparts.

Dark Worlds are home to a population known as Darkners, who differ from the Light World's population, referred to as Lightners. As with their surroundings, most Darkners correspond to items found in a Dark Fountain's immediate vicinity, or ideas related to them.

The Dark Fountains are important phenomena in the plot of Deltarune. Dark Fountains are large, gushing pillars of darkness which any "determined" Lightner can summon. Within the Light World space in which they are created, these Fountains give form to a localized Dark World. The "will" of a given Fountain is reflected in the Darkners who inhabit the world it creates. When a Dark Fountain is created in the Light World, it takes the form of an opaque black fog that fills the location it was made in. Sealing new Fountains has been the heroes' primary goal in each Chapter of the game thus far.