Ryuji Takane, son of a deceased professional boxer, nurtured a deep resentment toward boxing despite his natural aptitude, raised alongside his protective older sister Kiku. When their mother’s remarriage to an abusive drunkard escalated, Kiku’s violent intervention forced the siblings to flee to Tokyo, propelling Ryuji into a relentless quest for boxing stardom—pledging to reclaim their future by lifting their mother from hardship.

His defiance shifted to ferocious ambition after a humiliating defeat by Jun Kenzaki, a prodigy whose arrogance sparked an explosive rivalry. Guided by Kiku’s tactical brilliance, Ryuji honed unorthodox techniques: the whiplash Boomerang Hook, the devastating Double Boomerang, and the precision-driven Winning the Rainbow. These skills carved his path through Team Golden Japan Jr.’s brutal circuit, clashing against caricatured international foes—Black Shaft’s scrappy American brawlers, the lethal Shadow Clan, and the mythically overpowered Team Greece. Each battle battered his body and resolve, yet he refused defeat, fighting through shattered bones and bloodied resolve.

His dynamic with Kenzaki thawed from hostility to grudging camaraderie, climaxing in a near-fatal professional match where both men teetered on death’s edge. Ryuji claimed victory but collapsed post-bout, his life ebbing at Kenzaki and Kiku’s wedding. He died clutching his championship belt, a quiet smile sealing his fractured legacy.

Years later, his nephew Rindo Kenzaki inherited Ryuji’s indomitable spirit in the sequel series, confronting the scars of his uncle’s career—chronicling how glory and violence intertwined, leaving bodies broken even after the final bell.