Once upon a time.
In 2003, the Tokyo Manji Gang are founded by Mikey, Draken, Mitsuya, Pah-chin, Baji, and Kazutora. Kazutora convinces Baji to help him steal a motorbike for Mikey's birthday. During their heist, Baji realizes too late that the shop is owned by Mikey's older brother, Shinichiro, who Kazutora impulsively bludgeons to death. As he and Baji are arrested, a guilt-ridden Kazutora enters a catatonic state and reasons that the incident is Mikey's fault, therefore he must kill Mikey.