Maou no Musume-tachi

Once upon a time, Maou Amon terrorized in the land.
He led his army to attack towns and villages, spread destruction and slaughter. Nothing was able to slow him down (except his concern for animals being caught in the battles) and the whole world was about to fall into his hands.

Then a knight stormed his castle and defeated many of his minions singlehandedly.
Driven by boredom, Amon granted the knight Serenn an audience, who then demanded of him to stop.
After some negotiations (and Maoupunching) Amon accepted her offer to go with her when she promised he wouldn't be bored that way.
Abandoning his army (except for his right hand/lover Chilul), he moved in with Serenn near a small town.

Shortly afterwards, Serenn introduced him to Jem, whose parents had died in one of Amon's raids, and Tinna, a half-demon orphan, who she had adopted, and "asked" him to raise them while she fulfilled her duties as a knight in the capital.

And so Maou Amon's new life with his daughters begins...

[Translated from Getchu]