Kai Gang

A gang led by Kai Yasunori, he had troubles at school and work and left home and formed a gang with other unemployed youth and school dropouts, they had less than 10 members. His gang got involved with a lot of minor crimes, they mugged students from all schools that got both Kurotaki Alliance and Housen after them. Kai Gang also attacked Inada Genji, that got T.F.O.A. against them, but Yanagi Shinji was a childhood friend and tried to talk Kai out of it.

In one of Kai encounters he pulled a knife and cut Iwashiro Gunji's face, later Gunji found and beat him. After that Kai snapped and said he would kill everyone, from Suzuran, Housen, Kurotaki, T.F.O.A., didn't matter, and the first one he found was Genba Hisashi. Later T.F.O.A. got Kai trapped in a building, Yanagi begged to Takeda Kousei for another chance to talk to Kai, but Kai attacked him. Kousei then knocked out Kai.

Kai later turned himself to the police and was sent to juvenile detention. After serving his sentence, with Yanagi's encouragment and support he joined T.F.O.A..

While that all the remaining members were scared of the gangs hunting them and wanted to leave the town, it was then that their friend Akazawa Youichi said he knew a guy from Tokyo that was in town and could help them, he called Toshio and hired Kuzugami Tatsuo to hunt down the New Four Kings.
After Tatsuo beat Takeda Kousei and King Joe they regret hiring him as he was too sadistic, but it was too late. They were later found by the Suzuran freshmen and beat by them.