The world is slowly dying. Even after the Demon King was defeated, humanity continues to fade. The real reason? An overwhelming gender imbalance: nearly one man for every hundred women—and the gap keeps growing. Into this crumbling world, I was reborn as a boy named Dim. And for some reason, I'm humanity's last hope. Why? Because I possess a rare, god-given skill: "Sexual Champion." Yes, it's exactly what it sounds like. To save this world, I’ll have to build bonds, literally repopulate civilization—and survive the overwhelming attention of a desperate society. In a reversed world of chastity, where women rule and men are coveted, can one reluctant boy become the savior of mankind?