In a world where therianthropes, succubus, vampires, ogres, and many other demons live side-by-side with humans, Anthony Amasius is a unique existence: the only incubus in the entire world. He tries to live a normal life despite being what he is. He goes to college, has friends, and occasionally helps his diminutive professor when she needs some extra muscle. However, his world is about to be flipped upside when a War Maiden from Custodes Daemonium comes knocking on his door. If Anthony doesn't learn to embrace what he has become, he will never survive the coming storm.