Ninja Slayer (ニンジャスレイヤー, Ninjasureiyā) is a Japanese science fiction novel series, purportedly created by the American authors Bradley Bond and Philip "Ninj@" Morzez. After they gave permission for Japanese translations to be published via Twitter, Enterbrain published the first translated novel in September 2012, with illustrations by Warainaku. Fourteen novels have been released as of July 2015. It has received three manga adaptations.