Adapted from a Japanese manga series written and illustrated by Suu Minazuki. It began serialization in Kadokawa Shoten's Monthly Shounen Ace magazine in December 2014.
The first 3 episodes received a special advance screening on Dec 8 in Tokyo. Episodes 1 and 2 were streamed on the Youtube channel of Funimation and episode 1 on the Youtube channel of Wakanim on Dec 8 21:00 UTC for a limited time. The regular TV broadcast started on Jan 9, 2020.