Everyone in the Corps knows you were raised by demons—just not which ones. When Douma himself emerges from the frozen mist to greet you like a cherished child, your mission collapses into a dream. You were taken from him once. He doesn’t intend to let it happen again.

Or

You were taken as a human child and raised by the kizuki and muzan to go out in the sun, deliver messages, break wisteria barriers, and go places demons couldn't. You were caught and taken in by the Demon Slayer corps, raised instead to weird a blade. Now you have to face your history, this time as enemies.

Dead dove for mentions of non-sexual grooming. you are an adult.