A curious boy who asks a lot of questions. He is talkative and loud but seems to get along well with his friends. He is arch-enemies with Subin. He is characterized by his spiky hair. His catchphrase is "Oh shit." He uses a lot of profanity.

A timid boy who is very self-conscious but is obsessed with girls. He wears glasses. His catchphrase is "Agh..."

A boy with a disability who has no arms or legs, but possesses a truly positive and cool personality. A robot takes care of him, and he gets around in a wheelchair. He has an orange buzz cut. His catchphrase is the sound of his laughter, "Te-heh." He occasionally uses profanity.

An AI robot. He can be considered male and is very intelligent. His role is to assist Hyuk. He mostly lives at the school. However, the robot is also somewhat abnormal and uses a lot of profanity. He is rude but reliable.

A boy who isn't necessarily quiet but only says what is necessary. He is a collector of adult videos. He attracts many girls because of his "delinquent" look, but he isn't interested. He has a brownish-red wolf cut. Seeing as he holds his phone even during class, it seems the teacher has given up on him.

A feminist girl who cherishes female students and hates male students, calling them "Hannams" or "Hannam larvae." She knows she likes Yoon Jiwoong but denies it. She has a bob cut.

A child with zero presence. Although she is a girl, due to her parents' abuse and gaslighting, she believes her gender is a "Crayon." She is eccentric and has long black hair with a blue headband.

Subin's friend, a feminist and vegan girl. She is very quiet and tends to speak to Subin only in whispers. She has black glasses and a black short bob.

The class president of 4-3. She is timid, wears red glasses, and has a bob cut. Her secret hobby is BL (Boys' Love).

The homeroom teacher of 4-3 who is PC-minded but sincerely cares for the children. She has brown, medium-length hair.