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 the one for him, and begs to suck his blood. Hiroto was reluctant at first, but finally decides to offer his blood to Rio. However, when Rio kisses Hiroto, he realizes that blood alone is not enough...?! (Source: Shueisha, translated) Note: Chapter count includes two bonus short stories.