Tokyo Revengers (Omnibus) Vol. 11-12 (manga)

The Black Dragons are a brutal, bloodthirsty motorcycle gang, and their merger with Toman caused it to rot from the inside. Upon returning to the past, Takemichi collides head-first with Shiba Taiju, the leader of the Black Dragons, and his younger brother Hakkai. There’s a twisted history of abuse and loathing between these brothers, and Takemichi knows that someday it will end in murder. To keep Hakkai from staining his hands with his brother’s blood, and save his girlfriend’s life, it’ll take an unlikely alliance and a bare-knuckled Christmas brawl!