Tokyo Revengers: Seiya Kessen-hen

Despite his best time-leaping efforts, Takemichi Hanagaki continuously fails to prevent the present-day death of Hinata Tachibana, his adolescent love. The adult Takemichi grapples with grief and the ramifications of the Tokyo Manji gang's criminal empire—an unintended product of his timeline meddling. Though the gang once operated under the idealistic Manjirou "Mikey" Sano, it has now been taken over by the malicious Tetta Kisaki and, as a result, has abandoned its original optimistic intent.

Despite feeling hopeless, Takemichi travels to the past once again to investigate Black Dragon, a rival motorcycle gang whose actions ultimately lead to Hinata's demise. There, he meets the young Hakkai Shiba, a fellow gang member whose older brother, Taiju, tyrannically rules Black Dragon.

Takemichi, with Chifuyu on his side, works to unravel the fates of Black Dragon's members, fighting to create a happy future for his loved ones.

(Source: MAL Rewrite, edited)