Kimi wa Gochisou

In a world where humans coexist with demi-humans, such as vampires, werewolves, and succubi; Hiroto, a university student, meets Rio, a vampire who is looking for a "fated partner." Rio says Hiroto is his fated partner and begs to suck his blood. Hiroto decides to provide blood, although he refuses at first. However, when Rio kisses Hiroto, he realizes that blood alone is not enough...?! (Source: Shueisha, translated)