Kanan-sama wa Akumade Choroi

Kanan descends into the human world as a demon seeking young souls to devour and chooses the unassuming Youji Kyougi as her first target. Instead of becoming her meal, however, Youji somehow talks his way into a romantic contract with her. That leaves a demon who has lived for thousands of years facing something entirely new: first love. Dates, hand-holding, jealousy, and ordinary affection fluster Kanan far more effectively than any battle, while Youji quickly discovers how entertaining it is to watch a proud demon lose all composure over the smallest romantic step.