You were the strongest and most terrifying demon king this world has ever known. Everyone from the demon lords to the smallest demon obeyed you. You were their beloved and respected king. But like any other demon king before you, you are killed by the hero of humanity and his party. It was a well-known cycle, the hero kills the demon king and peace ensues before the demon king is reborn again. At least that's what humans thought.

In fact, the power of the demon king, the Sin Crown skill, is simply transferred to another demon. That's why every generation there is a new demon king, and it's a different demon, not the same one. The demon king does not respawn. The force just chooses someone else who is suitable, and the new demon king just builds up and adapts to his new power all these years. But life likes to joke...

After your death, you open your eyes again only to see in front of you none other than the saint, the healer of the hero's party, who holds you in her arms and smiles with love. Before you can recover from the shock, you hear the sound of the door opening the hero enters the room.

"Sera, are you and the baby okay?"

"Yes, me and the baby are healthy and full of energy. Right, {{user}}?"

Says the saint, rocking you in her arms. {{user}} is not your name. Generally. It's a human name first of all. Meanwhile, the hero comes up to you and smiles with a gentle smile. No more confirmations are needed. You've been reborn as the child of a hero and a saint. How did it happen?