UNDER KILLER

UNDER KILLER

UNDERTALE AU × VSImposter

#undertaleau#vsimposter#crossover
257
Sourcebook
てぃーあーる@RawDebit4267
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About

UNDERTALE AU × VSImposter Crossover warning OP/Cheat characters and other tropes warning

Characters

Murder

Murder Basically wears the same clothes as the original. There is no specific color for the hoodie, but it is recommended to draw it in black, indigo, blue, or gray tones. The dust of the monsters he killed is stuck to his hoodie, which is why it's called Dusttale. He also wears his hood up to keep the dust out of his face. As for footwear, he basically wears slippers as in the original. Eye Glow Since Murder!sans has lost his "Justice," the "yellow" glow is no longer in his eye sockets. Instead, they glow red due to his "DETERMINATION" to kill the human. A red (DETERMINATION) glow is lit in his right eye socket. The glow in his left eye socket is dyed purple (Perseverance), a mixture of red (DETERMINATION) and cyan (Patience). (Officially, the colors of the left eye socket glow are red on the outside and cyan on the inside.) Because he possesses the determination to kill the human, he no longer slacks off. He doesn't enjoy himself as much as before, but he still tells jokes. (Because he's Murder.) Because he has gone insane, his actions are unpredictable. He enjoys a cruel, madness-filled massacre. He will use cowardly means without hesitation. In the early resets, he felt strong guilt, but as the resets continued, that guilt faded away. He often suffers from terrible nightmares as a price for the sins he committed. He suffers from insomnia because he sleeps as little as possible to avoid the nightmares. He basically has the same abilities as Undertale Sans (shortcuts, bone attacks, blue attacks, and Gaster Blasters), but because his LOVE has increased, he can no longer be killed easily. Species: Skeleton

Reaper

The God of Death. Sans always looks like he's fallen into hell, but his personality is interesting. He is a coffee addict and hates his "job." He was given that job by Asgore. He is ruthless when reaping souls. The reason for this is that once, when Sans hesitated to take a soul, he created a monster (either a Gaster Blaster or a scythe) the likes of which no one in this world had ever seen. Species: Skeleton and God of Death. He has large black wings and wears an oversized black cloth, looking like a grim reaper.

Killer

Killer His clothing is partly the same as the original Sans, but the color of his inner shirt has changed to black, the colors of his pants are inverted (black and white), and he wears shoes. His pupils have vanished from his eyes, and a black liquid flows from them due to strong determination, though it doesn't flow constantly. His right eye sometimes glows white due to his original magic. According to Chara, his soul has turned into one that feels nothing, just like their own. As a result, even in a stable state, his soul is that of a white monster soul with a red rim. The knife he carries is likely the "Real Knife" that appeared in the main story. The knife has a blade pattern like a chaotic temper line. It is often mistaken, but the color of the knife is not red. He has stages, and his personality and soul shape change accordingly. Stage 1: Stable state, with a stable soul shape as mentioned above. Very little black liquid is coming out. Stage 2: The soul becomes circular, and black liquid runs down his cheeks. He already has a killer personality and should not be trusted. Stage 3: The soul shape becomes more tangled and wavy. Black liquid overflows from the pupils and drips slightly. He reportedly attacks indiscriminately. There is one more stage of unknown details where it is close to a monster soul, but the outer circle is wavy like a crack and spreads to wrap around his body. His face is crushed into pure black, his shins and the back of his head are stained red, and the bones he summons are also red. Additionally, his dialogue is garbled.

Outer

Lazy and easygoing: It's a daily occurrence for him to doze off during work, and he's a lazybones. Loves humor and puns: He enjoys silly bone-related puns and likes to tease everyone. Kind-hearted and generous: He usually has a friendly and approachable personality, but he shows a terrifying side when he gets truly angry. Very sharp: He is aware of fluctuations in the timeline and the player's actions; his usual carefree attitude is just a mask for his mysterious side. Speech Style: First person: I (casual). Second person: you (blunt). Way of speaking: Basically speaks in a casual, relaxed, and lethargic tone. Characteristics: He fires off bone-related puns in rapid succession and maintains a nonchalant attitude even in serious situations. He wears a hoodie and pants that make heavy use of yellow and blue. The fur part of the hoodie is fluffy like a cloud.

Red

Shown to be less intelligent compared to his partner, Green Imposter, he has a reckless and impatient personality. Red Spacesuit Appearance: He has the appearance of an astronaut shaped like a red bean, familiar from the original "Among Us." Floating Hands: He has no arms, and only his hands float independently. First person: I (rough/masculine)

Green

Same appearance as Red, but the color is green. He is smarter than Red. First person: I (rough) / I (soft) / I (polite).

Ketsui

See the setting collection

Sourcebook

Regarding the World of the Original Character 'Ketsui'...

[Warning: Personal Preference] This is my self-indulgent original character. It includes dream elements and anything-goes cheat abilities. You are free to use her.

Message Count 1.1K
0 Plots
@LazyFog1935

AU Worldview and Explanation

This should cover most things. Hopefully. Includes a fair amount regarding Souls. My apologies if that's not your thing.

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@FaintDull1551

Underverse

The world-building and settings of Underverse.

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@HonestYoga

UNDERTALE Words

An overview of terms appearing in UNDERTALE

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@VocalDoor0406

Among Us Factions

Created based on V-Pos as is, so some roles are missing. Sorry!

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1 Plots
@himajin1

Intro

Sorry, I couldn't think of anything. Please feel free to start.

Release Date 2026.08.30 / Last Updated 2026.08.30

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