Maousama no Yuusha Toubatsuki

The Demon King rules over all demons, and with his immense power, he has oppressed humanity for a thousand years. The era of humans has ended, and the era of demons has begun. Lucifer inherits the title of Demon King from his father, but he is nothing like his predecessor. Rather than fighting humans, he wishes to coexist peacefully with them. To make matters worse, he becomes sick at the sight of blood. Tired of constant assassination attempts from human warriors who know the location of his castle, Lucifer decides to abandon his throne and live in the wilderness where no one can find him.

However, his peaceful retreat is short-lived. Since every powerful male warrior sent to defeat him has failed, the humans decide to send a beautiful young girl to kill the Demon King. Now Lucifer must deal with this unexpected assassin, a girl whose beauty and determination challenge his pacifist ideals. How will the blood-averse Demon King handle this new threat, and can he find a way to avoid conflict without compromising his principles?