Oresama na Doukyuusei no Kenzoku ni Narimashita

A boy who doesn't keep his word must be disciplined, right?
In a world where human and non-human descendants coexist, Rio is a high school student descendant of vampires. As a result of his race, he's feared by his classmates and he tries hard to go unnoticed. Independently of his intentions, Kairi, a human classmate, is always bugging him. Due to Kairi's tactless words, the girl Rio likes hates him and in his desire to seek revenge, Rio decides to make Kairi his "servant"?!