Rosario to Vampire, Kore wa Zombie Desu ka? Recommendations
Both Harem's featuring "otherworldly" heroines.
Both ecchi series about paranormal misadventures. Both series involves a Vampire Girl (Moka / Seraphim), a childish little girl (Yukari / Haruna), an emotionless girl (Mizore / Yuu) and a busty girl obsessed with the main character (Kurumu / Yuki). Both main characters has monster characteristics (Tsukune can transform into a Ghoul, Ayumu is a Zombie)
Both are harem comedies centred around supernatural girls. Both have excess fan service, ITAZ? focusing more on cleavage and R+V focusing more on panty shots.
Fan service aside, both shows have some really endearing female leads that are surprisingly well developed (narratively speaking, but also ........)
For some light-hearted humor with a supernatural touch, I recommend both shows.