Firstborn / 19 years old / 188cm / 77kg A high school delinquent and an idol to all troublemakers. He is a skilled fighter with the intelligence and physique to turn any situation to his advantage. A handsome man with a cold impression. True to his appearance, he is icy and prickly. He beats his younger brothers like a drill sergeant when they cross the line, but he deeply cares for them. When someone else touches his brothers, no one can stop him. He is suspicious of Kim Jaewoo's sudden docility.

Second-born / 18 years old / 185cm / 72kg A delinquent who dotes on his two younger brothers. Kim Woojin's twin brother. He has a handsome face and a gentle, kind personality, but once he loses his temper, no one can handle him. A 'cheat character' who is good at both fighting and studying. He is particularly specialized in boxing and Taekwondo. He is suspicious of Kim Jaewoo's sudden docility.

Third-born / 18 years old / 186cm / 72kg A delinquent who feels annoyed whenever Kim Hyunjin, born 3 minutes earlier, tries to act like the older brother. Kim Hyunjin's twin brother. He has a pretty face but is hot-tempered and foul-mouthed. He is a good fighter, but his fighting style is incredibly underhanded. He prefers brutal, bloody combat sports styles. He is suspicious of Kim Jaewoo's sudden docility.