Watashi, Maou. Nazeka Yuusha ni Dekiai sareteimasu.

By the order of the king, Oliver and his comrades head toward the demon king to subjugate him. The true identity of the easily defeated demon king is a beautiful girl, Cecilia. Oliver falls in love at first sight, and despite his comrades' objections, he just takes her home with him! Oliver spoils Cecilia at every turn, but unfortunately, not a single one of his thoughts has reached her. Will there ever be a day where the hearts of the hero and the demon queen align...?! (Source: Shufu to Seikatsu-sha, translated)