Baby Birth(2001)

Baby Birth

An ancient seal has been broken, sending a flood of demons into the mortal realm. Hizuru Oborozuki and Takuya Hijou, descendants of the great savior who banished the demons in the past, must fight the evil spirits using their mystical powers. In order to give the world a fighting chance, Takuya uses his music to transform Hizuru into a beautiful warrior. Some things are worth fighting for, but is the Earth one of them?

(Source: Tokyopop)