Kami nomi zo Shiru Sekai

Keima Katsuragi is a high school student better known online as the "God of Conquest," the man who can obtain the heart of any dating sim girl. In his opinion, real life is an awful game; three-dimensional girls are annoying and false representations of how a real girl should be. One afternoon, while taking a break from cleaning duty, he stumbles across a strange message that goads him to conquer a girl. On a whim, he accepts, and his consent summons a girl named Elucia "Elsie" de Lute Ima, a denizen of hell tasked with capturing runaway spirits that have festered in girls' hearts. Keima is shocked and tries to escape, but Elsie tells him that failure to fulfill the newly formed contract will result in the termination of his life! Tasked with capturing the runaway spirits, Keima uses his expertise and knowledge of dating sims to obtain the hearts of girls in real life.