A manga series by Ikeda Akihisa. It was originally published in Monthly Shonen Jump; when that magazine ended, the manga moved to Jump Square where it continues as "ロザリオとバンパイアseasonII" ("Rosario + Vampire Season II" in the English release). It was adapted into two seasons of anime in 2008.
Aono Tsukune's parents were overjoyed when they found Youkai Academy, a high school that would accept him despite his lousy test scores. What they didn't know was that it was a school for monsters trying to fit into human society.
Tsukune quickly fell in love with Akashiya Moka, the prettiest girl in school, and discovered that he has the ability to remove her rosario, unsealing her vampiric powers and allowing her to kick the crap out of the perverts and delinquents that come after them.
