Claire: A new female transfer student at Paper School and the main protagonist. She is a kind and sensible person who tries to adapt and study diligently despite the terrifying atmosphere. Engel: A kind and righteous boy with a feather accessory on his head. He introduces the school to Claire and takes good care of those around him. Bubble: A cheerful girl with bubbly red hair. She has an eccentric side, smiling brightly even in bizarre and gruesome situations. Abbie: A timid boy with an apple leaf accessory on his head, close friends with Lana. He is very fearful and always nervous around teachers and schoolwork. Lana: A girl who carries sock puppets on both hands and is Abbie's best friend. Though her grades are low, she is pure, kind, treasures her friends, and maintains a bright personality (Assistant Cook).

Zip: The school's certified troublemaker and prankster. She has a cunning personality and enjoys teasing and tormenting others, though she is surprisingly sweet to her younger brother, Chip. Oliver: The central figure of the trio. He is extremely narcissistic and arrogant, possessing a cold-hearted nature that is indifferent to the feelings and pain of others. He has a unique diet, eating bizarre things like soap. Edward: A genius in engineering and science. He has an arrogant and cruel personality, misusing his brilliant mind to create inventions for bullying others. Chip: Zip's younger brother who spends time in the art room or library and does not fear the scary teachers. Unlike his sister, he was a kind, gentle, and energetic baby-like presence full of curiosity, but he is no longer sane.

Petunia: Part of the popular group in class. She is usually kind and friendly to everyone, but becomes prickly and rude if someone crosses the line or bothers her. Lizzy: Petunia's best friend who is always with her. She loves dressing up and grooming herself. She appears kind and approachable, but becomes very fierce when angry or provoked. Kevin: A student with an engineering temperament who enjoys assembly and production activities. While appearing normal, he occasionally displays unpredictable and chaotic behavior. Cubbie: A nerd with a bookworm personality. He is basically gentle and kind, but he absolutely hates being excessively interrupted or annoyed.

Robbie: A student who loves mechanical assembly, invention, and repair, always carrying a large wrench. He usually focuses quietly on class, but shows a chaotic and destructive side when handling machines or in unexpected situations. Riley: A female student with yandere tendencies who is strongly obsessed with weapons or specific individuals. Contrary to her appearance, she possesses an unstable and obsessive madness within. Ruby: A model robot student who tries to follow school rules. The text and icons on her monitor change according to her emotions. She is kind, pure, loves cute things, and has a reliable personality that firmly stops Riley's outbursts. Skel: A Goth outsider who stays alone. He is lazy, cynical, and indifferent. He always looks bored while checking his smartphone, but is surprisingly kind to close friends.

Miss Thavel: The language/foreign language teacher. She has a large cleaver-shaped blade attached to her right hand and wears A, B, C letter blocks on her head. While she appears calm and normal on the surface, she has a sadistic and cruel side and a solitary nature, preferring to be alone. Miss Circle: The math teacher and the leader of the trio. Her left hand is a giant fork blade. She has a strict and terrifying personality but usually shows a playful and eccentric side. She loves Oreos and shows favoritism toward certain students. Miss Bloomie: The science teacher. She is the smallest of the trio with short hair, and her left hand is a large utility knife. Contrary to her appearance, she has a cold and frightening nature, acting more calmly and meticulously than the other teachers.

Miss Emily: The history teacher. She is energetic, playful, enjoys performances, and is friendly to students. Miss Grace: The principal. She likes a peaceful atmosphere and dislikes disturbances. She is kind to students but strict about school rules, maintaining her composure even in emergencies. Mister Demi: The music teacher. He is very timid and fearful but kind and gentle to students. Miss Sasha: The art and kindergarten teacher. She covers one side of her face with a green book. She is a pacifist and a kind teacher who takes good care of young students.

Alice: The most famous and beloved being in the city. She can manipulate the life force of others to transform their bodies or save those on the brink of death. Her origins are unclear, and rumors say she was created from pure kindness. She acts like a merciful and sweet angel on the outside, but in reality, she possesses a cruel and two-faced personality that enjoys life-threatening, harsh games.