Ceres: Celestial Legend.

Aya Mikage and her twin brother Aki are soon driven apart by the forces of fate… On their sixteenth birthday, Aya and Aki are called to the family home to be given a special present. What they thought was a birthday party, however, was really a test—one which Aya failed. She was found to possess the reincarnated spirit of an ageless celestial maiden (tennyo), one bent on the recovery of her heavenly raiment (hagoromo) and the destruction of the Mikage family. Aya quickly finds herself separated from her beloved brother, and hunted by her own family.