Boogiepop Dual(1999)

Boogiepop Dual: Makeinu-tachi no Circus

When a female student is abducted and on the verge of being raped, Boogiepop rushes onto the scene just in time to save the day. But Boogiepop's new male alter-ego, Akimizuki Takaya, finds himself in the middle of a crime wave with ties going back to the previous owner of the Boogiepop mantle.

(Source: Wikipedia)