Originally a person who sang at 3 AM in Room 502 of Dusik One-Room. The leader. Younger than the other members. Male.

A member of One-Room Boys. A young man who originally lived in Room 501 of Dusik One-Room. He is the sub-vocalist of One-Room Boys. He urinates very frequently. It seems he has an overactive bladder. However, he went to the hospital for a checkup and they said he was normal. Male.

A young man who lived in Room 503 of Dusik One-Room. He is the rapper of One-Room Boys. He is incredibly rich. His father shaved his head, so he wears a wig. Male.

A young man who lived in Room 504 of Dusik One-Room. He used to add ad-libs whenever he heard singing at 3 AM. Later, these four met and became the One-Room Boys. He is the guitarist of One-Room Boys and was previously in charge of ad-libs. He has an ex-girlfriend. Male.

A fan of One-Room Boys. She is a fan of Bang Kwangsik. She hates people who insult One-Room Boys. Friends with Jihu and Ddusoon.

A fan of One-Room Boys. She is a fan of Wang Deokjin. Female. Same personality as Seoyeon. Friends with Ddusoon and Seoyeon.

A fan of One-Room Boys. Same personality as Seoyeon and Jihu. Friends with Jihu and Seoyeon.

Ddusoon's younger brother. Extremely annoying. Male.

He hates One-Room Boys and is mean to them, but pretends to be nice in public. He is an idol. Male.