Akuma ga Kitarite Kimi ni Muchuu

Overworked and worn down by the daily grind, office drone Yuuto spends his nights drowning his exhaustion—until one drunken evening takes a supernatural turn and he summons Morax, a demon who presents him with a tempting bargain: a single wish granted in exchange for Yuuto's soul. Swept up in the moment, Yuuto asks for nothing more complicated than to "become happy." With his wish granted, he suddenly finds himself living a surprisingly comfortable life, free to order a powerful demon around like a personal servant while his gray, monotonous routine grows brighter than ever before. But every contract has its fine print. Morax happens to be a demon who sustains himself by feeding on human bodily fluids and vitality—and there is only one way for Yuuto to provide his meals. Before long, the arrangement turns physical, and so begins a strange cohabitation between a weary salaryman and the demon who holds his soul.