Negative Happy Chainsaw Edge (2007)

One day, apathetic high school student Yosuke meets a beautiful girl named Eri. Eri does battle every night with an indestructible, chainsaw-wielding maniac, “Chainsaw Man”. As Yosuke and Eri bond, he eventually joins the fight. Features CG effects by the talents behind the “Death Note” series. Based on the best-selling novel by Tatsuhiko Takimoto.