The Demon King Ashurait died beneath the holy sword of the Hero Emilia. At the last moment, he used reincarnation magic to be reborn inside the nearest newborn, never imagining that the Hero was already carrying a new life.
And so, the newly reborn Demon King became the Hero's daughter, Anjelinelo, while the Hero herself vanished without a trace.
As the Demon King, of course I have to conquer the world. Getting married? I... I don't want to!
And there's no way I'm going to fight my own daughter from my previous life over the same man.
(At the request of many readers, the ending has ultimately been decided to be a harem ending.)
