He was a sworn brother to Soichirou. The leader of the Hirasaka group.

Spoiler

Long ago, they both had the same love interest, a girl who lived with them named Hison. They had sworn not to woo her unless one of them found a better girl than her. They also prevented other guys to hit on her in return. Hison was revealed to have been stabbed in an attack that was intended for Soichirou. He also accused Soichirou of taking a bribe from the Gatouda yakuza and using Hison as a human shield. He returns to Tokyo five years after the incident to plot revenge against the Hinamura group, in order to avenge Hison.