Rosario + Vampire 2nd Season

Tsukune Aono has completed his first year at Youkai Academy, where he's the only human among supernatural students. His life is complicated by a large and varied group of female admirers, including Kurumu Kurono, Yukari Sendou, Mizore Shirayuki, and Moka Akashiya, a vampire who exhibits a darker personality when her rosary is removed. Moka's younger sister Kokoa Shuzen appears, intent on releasing her "true older sister" from the rosary, but her actions may have unintended consequences.