Kenka no Gokui 4.

Expecting another enemy, Haru is instead approached by Sho, a bespectacled honor student from an elite prep school. Sho, partnered with the ruthless Kenshin, is running an underground fight ring called “Fight Club” and tries to recruit Haru. Haru refuses to turn fighting into business—but the Fight Club targets his friends to force his hand. The club leader is beaten senseless, Shingo is sent to intensive care, and the ring ignites with delinquent pride on the line.