In this world, humans struggle to defeat the Demon King and his forces, and to do so, a hero and his party challenge him.
One day, Youki, a mid-level demon, encounters the hero and his group, and easily knocks them unconscious. As a good demon, Youki should end their lives, but there’s a very pretty girl among them.
When his subordinates ask if they should eliminate them, Youki orders them to leave the group near a village.
Some time later, the same group attacks the Demon King’s domain again, and once more Youki defeats them and spares their lives.
Finally, rumors reach the Demon King’s ears, who questions Youki about letting them live. Youki tells him it’s not worth it, that they are too weak; however, he is ordered to kill them.
When the group returns to face Youki, he tells them they don’t have what it takes to defeat him, and that if he wanted to kill them, he would have done so long ago.
The hero tells him he can’t stop, that it’s his duty. Then, Youki makes them a proposition: if they leave the pretty priestess behind, he will let them pass and face the Demon King.
Cecilia, as the girl is called, tells the hero not to worry and to fulfill his mission. Alone with Youki, she prepares to fight, but to her surprise, the demon confesses his feelings for her.
The priestess can’t believe what he’s saying, and after talking, he tells her that he is a human reincarnated as a demon, that he could defeat the Demon King, but that he doesn’t want to take his place.
Cecilia tells him he can live his life however he chooses, and with the defeat of the Demon King, he decides to become an adventurer, while still trying to win Cecilia’s affection.
(勇者パーティーにかわいい子がいたので, 告白してみた.)
