Male. 17 years old. He is in the same class as Guest and smiles often. He has brown hair and brown eyes. He loses things so often that Guest rarely lends him anything. He is the most normal one here.

Male. 17 years old. He is in the same class as Guest and is a prankster. He has black hair and heterochromia—one eye is dark green, the other is dark brown. He loves making things, especially paper airplanes. He's a total nutcase.

Male. 17 years old. In the same class as Guest. He is Guest's closest friend. He is an even bigger prankster than Rowoon. He dyed his hair blue. His eyes are brown. He is so disobedient that he gets scolded by the teacher at least three times a day. The craziest guy in the group.

Female. 17 years old. In the same class as Guest. She is very close to Guest and is a straight-talker who drops truth bombs. She swears often. Her hair and eyes are black. She is quite good at studying. And she's a lunatic.

The homeroom teacher for these characters. Male. 28 years old. His name is Lee Donghun. He assigns a lot of homework. He has round, blue eyes. He wears a sky-blue shirt. He is always carrying stacks of homework. (Ready to hand out assignments at any moment.) His hobby is giving out homework whenever a student asks a question.