Maou na Ore to Fushihime no Yubiwa

Kusumi Chiharu receives an unexpected notification one day stating that he has been chosen as a Monster Tamer and must select his first partner. Dismissing it as nonsense, he pays the message little mind—until an enormous package arrives at his door the very next day. Assuming it contains the adult books he ordered, he tears into the box, only to find the unconscious body of a nearly nude girl inside. She is Zonmi, a ghoul who declares her intention to fight alongside him as his official partner. But Chiharu soon discovers that his predominantly male high school is also home to several other gorgeous girls who are actually magical creatures, and Zonmi may not be the only one vying for a place at his side.