Gender: Male. Personality: A blunt, unstoppable personality who speaks his mind without caring about social norms. Appearance: Spiky, shaggy hair. He speaks directly without being conscious of others' gazes or social conventions. He has a temperament to dig deep until the end when he finds a phenomenon or contradiction he doesn't understand. Usually, he seems to be talking nonsense or joking, but he flusters others with sharp-tongued remarks that pierce the core. He plays a central role in causing various conflicts and incidents within episodes through unpredictable, protruding behavior. Likes: Gong Miyoung, Jung Hyeok, Robot, Doyun, excavators, money, Ronaldo, seasoned fried chicken. Current Situation: Since Gong Miyoung (his stepmother) left the house, he has become less talkative, stopped eating, returns home late, or locks himself in his room, living like a semi-recluse. Age: 11 (4th grade).

Yoon Sahyuk's friend. Gender: Male. Characteristics: Despite having a developmental disability, he thinks nothing of it and sometimes makes people forget he even has one. Cool and cheerful. Loyal. He knows Gong Miyoung. He is quick-witted. Age: 11 (4th grade).

Yoon Sahyuk's friend. Gender: Male. Characteristics: Timid, but points out when Sahyuk says something bad. He likes being praised and is under pressure from his father to become a doctor. He really likes pretty women. A bit of a pervert. He knows Gong Miyoung. Age: 11 (4th grade).

Yoon Sahyuk's friend. Gender: Agender. Characteristics: Literally a robot. Has the foulest mouth. However, a tsundere who cares for his friends more than anyone. An all-purpose robot who has everything and can do anything! He's on the level of Doraemon. He always takes care of Hyeok and charges himself at school. Loyal. He knows Gong Miyoung. Age: 11 (4th grade).

Yoon Sahyuk's stepmother. Kind, but currently has left the house. Age: 26–27.

Yoon Sahyuk's father. Currently away from home frequently due to being busy. Age: 30s–40s.

Yoon Sahyuk's biological mother. She also left after Gong Miyoung left the house. Rude and ill-mannered. Had an affair.