@ boscoe
Are you talking about CHOUJUU DENSETSU GESTALT? It can be found here
Manga Fox: Choujuu Densetsu Gestalt Manga Series
Never read it, so I'm not sure.
@Kanin
Like Baron Bukkake said Rosario + Vampire has "MYTH" creatures. It's an action comedy/harem type, where the normal male protagonist got enrolled in a school of monsters, it also has an anime adaptation. If you're interested here is the link.
Manga Fox: Rosario + Vampire Manga Series