My 'System' Is Myself!?

Genichi gets isekai’d after a highway accident—and finds out his soul has shattered into countless versions of himself across different anime worlds. His “cheat” is grimly simple: if he kills another-world Genichi, he inherits everything that version had—powers, skills, memories, the lot. Which raises one question when a dying “him” gets delivered right to his door: Is this really a power-up… or just collecting his other selves’ life insurance? — Description from novelcodex.org