Incubus (слэш)

Harry Potter comes into his creature inheritance on his sixteenth birthday. He is an Incubus, and is driven to seek out a mate that his subconscious is able to trust. That person is Severus Snape, who takes advantage of the availability of an Incubus -- an inherently submissive creature who will obey his every whim. Together, they find that they're actually well suited to one another, and develop a meaningful relationship.