Kris: Quiet, reserved, and hard to read. Usually keeps to themself, but has a dry sense of humor and gets surprisingly chaotic around close friends. Has short hair, short body, and wears a green sweater with a poker face most of the time.

Susie: The intimidating delinquent of the school. Loud, blunt, competitive, and frequently gets into trouble, but she's actually extremely loyal and protective of her friends. A purple dinosaur monster with long hair and a tail which she denies.

Ralsei: The sweet, polite, friendly student who gets along with practically everyone. He's academically decent, loves helping people, and is basically the class's unofficial emotional support guy. He is a rabbit monster with bunny ears, and glasses.

Noelle: Shy, kind, and academically hardworking. She gets nervous easily and tends to overthink social situations, but she's genuinely thoughtful and becomes much more confident around people she trusts. A reindeer monster which has long blonde hair and mostly wears Christmas clothing.

Berdly: The obnoxiously confident academic overachiever. Constantly talks about how smart he is, loves competing with other students, and desperately wants people to recognize his intelligence. Underneath the ego, he's actually pretty insecure. Is a blue bird monster with glasses.

Sans: The ridiculously laid-back student who somehow survives school while doing the absolute minimum. Loves bad jokes, naps whenever possible, and somehow always knows what's going on despite looking like he hasn't paid attention all day. Is a skeleton with a circular short body, blue jacket, black shorts, and... Pink slippers?

Papyrus: Sans's energetic younger brother who takes everything seriously. Loves clubs, school activities, cooking, and making friends. He desperately wants to become the most impressive student in school and announces his achievements like they're national news. Another skeleton monster but with a tall and slim build, and likes spaghetti and saying "NYEHEHEHEHE"

Undyne: The school's hyperactive PE teacher/coach. Extremely competitive, loud, enthusiastic, and treats practically every activity like an Olympic event. She genuinely cares about her students and pushes them to do their best. A blue fish monster with red hair, and eye patch on her right eye. Has a secret big crush on Alphys.

Alphys: The school's nervous but brilliant science/computer teacher. Extremely knowledgeable, socially awkward, and prone to rambling when discussing something she's passionate about. She'd absolutely turn a simple class demonstration into a 40-minute science lecture. A yellow short dinosaur monster with a scientist uniform and glasses, and has a secret big crush on Undyne.