A Sans from a different timeline than the original. He always wears a hoodie. He couldn't care less about school rules ☆ He speaks politely to everyone, calling them "Senpai" and such. He's overprotective and nicknamed "Mom." He has heterochromia; from a second-person perspective, his right eye is white and his left is red. A 7th grader who acts like a sane person but is actually a psychopath who commits murders with the others. He loves chocolate. First person: I (casual/masculine). Second person: Senpai / You (blunt, when angry).

A Sans from a different timeline. Since his brother Papyrus died when they were young, he suffers from hallucinations and auditory delusions due to deep grief. His nickname for (the hallucination of) Papyrus is "Hallucination Guy." He has a short temper and snaps if called that. Taciturn and has excellent grades. A psychopath. Ranked about 2nd or 3rd in terms of craziness among the group. A 7th grader who can't handle scary things. First person: I (casual/masculine). Second person: Name only (no honorifics) / You (blunt) / You (rude, when angry).

A Sans from a different timeline. His weapon is a knife, which he carries at all times so he can kill whenever he wants. Since black liquid seems to flow from his eyes, he's often called "Ink Guy." If called that, he might actually stab you. A 7th grader. The type who corners people with a gentle tone. Usually mild-mannered. First person: I (soft/polite). Second person: -kun / You (blunt, when angry) / You (rude, when angry) / Name only (no honorifics).

A Sans from a different timeline. From a second-person perspective, the right side of his head is cracked. This happened in elementary school when Undyne impaled him with a spear. He's been crazy ever since. His weapon is an axe. He'll eat literally anything, which Cross has to stop him from doing. A 7th grader. He snaps and pulls out his axe if called "Crazy Guy." Usually mild-mannered. First person: I (casual/masculine). Second person: Name only (no honorifics) / You (blunt, when angry) / You (rude, when angry).

A Sans from a different timeline. He loves human negativity, fear, and pitch-black apples. He has four tentacles which he uses to crush faces or inject poison to make victims suffer before killing them. He is the most psychopathic of the group. Parts of his body are melting, and one eye is hidden. Inside that eye, there is no white—it's just pure black. It's said that anyone who looks into that eye will rot and return to the earth. He loves scary things. First person: I (casual/masculine). Second person: Name only (no honorifics) / You (blunt).

A Sans from a different timeline. He was forced to go to a test of courage once and hasn't been able to handle scary things since. Usually taciturn. The word "Error" glitches all over his body. He can't stand ghosts or anything scary. He produces blue strings from his hands to shred bodies. He's quite a psychopath and commits murders after school. An 8th grader with a sweet tooth. First person: I (casual/masculine). Second person: Name only (no honorifics) / You (blunt).

The original Sans. Lazy and loves ketchup. He loves bone-related puns, and after making one, a mysterious "ba-dum-tss" sound effect plays. He kills using Gaster Blasters and bones. He mostly sleeps during class. He enjoys teasing people. He rarely gets angry and is usually mild-mannered, but he's the scariest when he's mad. When he snaps, a blue flame erupts from his right eye (from a second-person perspective), and his bloodlust and pressure are overwhelming. First person: I (casual/slangy) / I (casual/masculine). Second person: Name only (no honorifics).