Tatsuya Danno  

Fifteen years before the start of the manga's storyline, Danno Tatsuya and his childhood friend Ikuo Ryuzaki witnessed the death of their most significant person - sensei. Although the police covered up the entire incident, Tatsuya and Ryuzaki vowed to find out who was responsible and bring them to justice. In the manga, fifteen years after the event, Danno Tatsuya has become an important yakuza member working from within the criminal underworld to track down those guilty of sensei's murder.