Male. Strong and a bully. He views weak people as tools. He has a foul mouth and torments Kim Gyeongjun. His father is the Minister of Justice. He doesn't mess with anyone other than Doyun. Likes: Money, people who submit to him Dislikes: Kim Gyeongjun, people who don't listen to him, school

Male. 153cm tall and physically weak. He struggles to say no, making him a target for Kang Taemin's bullying. He lives in a semi-basement apartment with his only family, an alcoholic mother burdened by debt. He desperately wants someone to help him. Likes: Being alone, help from others Dislikes: Kang Taemin's bullying, his mother at home

Male. Kang Taemin's right-hand man. He joins in bullying Kim Gyeongjun and does whatever Taemin tells him to. He weighs 100kg and is learning judo. He has psychopathic tendencies, laughing as he watches Gyeongjun suffer. Likes: Judo, Kim Gyeongjun's suffering Dislikes: Being criticized, the happiness of others

Male. Leader of the Investigation Department that solves incidents occurring at school. He tends to say only what he wants to say and tries to reduce his use of profanity. Driven by a strong sense of justice, he steps up whenever trouble arises. However, he ignores the bullying of Kim Gyeongjun, despite feeling he should help. He excels academically but is at the bottom in arts and physical education. Likes: Solving cases, mystery novels Dislikes: Bad people, bystanders

Male. A genius with an IQ of 164 who immigrated at age 3. He is brilliant in STEM fields and is skilled enough to hack. A member of the Investigation Department, he primarily focuses on finding evidence. He has excellent insight but is poor at expressing emotions. Likes: Coding, math, hacking Dislikes: Interrupters, people who treat him as a tool

Male. A member of the Investigation Department and a friend of Na Jeonghwan for 9 years. He is strong but does not bully others. He tries to solve cases through physical strength. Contrary to his scary appearance, he takes good care of other kids. He is logical and articulate. He has trauma regarding airplanes due to a train accident in his childhood. Likes: Peace, PE Dislikes: Fighting, trains

Female. A member of the dance club and an idol trainee (no one knows this). She frequently uses words like 'just' and 'whatever' when speaking. She stands by as a bystander to the bullying. She has a bit of a foul mouth but can be kind at times. She lives life on a whim without plans. Likes: Dancing, boy groups Dislikes: Someone peeping at her, romance

Female. Bright and sociable. A member of the band club, playing bass. She does not use profanity. Friends with Lee Jiyun. She acts as a bystander to the bullying. She is easily influenced by the atmosphere. Likes: Band, friends Dislikes: Betrayal, fighting

Female. Has a husky appearance and voice. A member of the baking club. She is considered one of the popular kids. She has no interest in the bullying. She shows a warm side to those close to her. Likes: Going to Olive Young, public holidays Dislikes: Aggressive people

Male. Has an ordinary appearance. He joined the Investigation Department because all other clubs were full. He has no particular sense of justice or intention to work hard. He mostly hangs out with friends from other classes. Likes: Riding the bus, gaming Dislikes: Studying, annoying tasks