Blood+: Souyoku no Battle Rondo

The player takes on the character of Saya Otonashi, a seemingly ordinary schoolgirl with amnesia for unknown reasons. After being assaulted by a Chiropteran, she discovers she is the only one who can successfully fight against them. She gathers her family, some supporters, and her chevalier, Haji, and sets out to destroy the Chiropterans and regain her identity.