One Piece: With My Giant Bloodline, I Have Many Kids and Great Luck

A burned-out programmer named Kaizer died at his desk and reincarnated into a mangled corpse amid the carnage of God Valley. Two gifts saved him: an immortal subhuman body and a forbidden system that rewarded him with power for every child he sired. On the brink of death once more, he was hoisted into the air by Charlotte Linlin, the future Emperor known as Big Mom. At twenty-four, her eyes burned with insatiable greed as she examined his broken yet regenerating form like fresh meat. "Mamama… Interesting. A toy that won't stay dead. You'll be breeding for me soon enough." — Description from novelcodex.org