When Kenichi Shirahama stands mere moments from claiming karate's world championship, a cowardly opponent ends his life rather than face defeat. Granted rebirth through reincarnation, he awakens with renewed purpose and boundless potential. His transformation from reluctant disciple to the mightiest martial artist unfolds across an alternate modern world, powered by relentless determination and unmatched skill. As Kenichi ascends to supreme martial supremacy, he simultaneously attracts and captures the hearts of multiple women, establishing his legendary harem while becoming unstoppable in combat.