Boku Ni Korosarero summary:

Yuu Yakushimaru, a truant junior high school student, spends his days hating his bullying classmates and sarcastic life guidance teachers, and dreaming of one day killing them all. When he gains the "power to kill" and discovers that the people he hates are monsters that he can "kill" - the killing spree will never stop!　Non-stop horror suspense, the curtain rises!