All pure-hearted Mamoru Hishida wants is to live as a decent human being. So he can’t figure out why his life keeps spiralling out of control. Then one night, he happens upon a beautiful vampire who immediately recognizes him for what he truly is—an incubus-human hybrid, and on the brink of sexual starvation. The vampire strikes a bargain with Mamoru to become his familiar in exchange for a supply of sexual energy...but are familiars usually charged with attending manga conventions? Thus begins a strange romance between a virgin incubus and a sensual, manga-obsessed vampire. - Hashida Mamoru just wanted to live as a genuine "human". In fact, he was a normal college student...except that he was a non-human thing-a child of a devil and a human. Mamoru, who is in a state of uncontrollable demon pheromone, was sick and sick because he had destroyed his apartment by a truck misled by the pheromone and had never taken any energy before. What helped him was an unhuman thing-a vampire Radu. "I don't want you to die," Radu tells Mamoru, who doesn't know how to instinctively as a devil, teaches sex and energizes him. And in exchange for him, he becomes a "familiar". What is the role of that familiar? A little Devil x Vampire