Intense [VertiComix]

The crime lord Yoonshik takes the little boy Jiwoon as collateral when the child's father hangs himself from debt. Eight years later, the boy is working as Yoonshik's bodyguard. When the boss gets locked behind bars, Jiwoon is sent to work for another middle boss in the city's red-light district. There, Jiwoon meets the mysterious Soohan, and everything begins to change. Intense series was originally published as donginji (doujinshi) in Korea.