Based on an action fantasy light novel series written by Nagashima Hiroaki and illustrated by Ichimaru Kisuke. It began on the Shousetsuka ni Narou website in January 2013. AlphaPolis began publishing the novel with illustrations by Kisuke Ichimaru in March 2015. The 24th volume went on sale on March 31. The series has a cumulative 1 million copies of its volumes in circulation.
Kurono began serializing a manga adaptation of the light novel this is based on in the AlphaPolis web magazine in December 2015. The 12th volume was released on March 31.