Akai Tenshi

Mika, a transfer student, is a girl as beautiful as an angel. She invites her new friend Nana to her house, where Mika's brother Koryu fascinates her. But between these beautiful siblings lies a hidden secret. They are actually vampires with red wings attached to their backs. They have survived for eternity, yearning to live under the sun's rays and drinking the blood of humans. (from DMP)