is a Japanese light novel series written by Hajime Kamoshida, with illustrations by Keji Mizoguchi. ASCII Media Works published 13 volumes between January 2010 and March 2014. A manga adaptation illustrated by Hoki Kusano was serialized ASCII Media Works' Dengeki G's Magazine and Dengeki G's Comic. A drama CD was released on June 28, 2012. A 24-episode anime TV series adaptation by J.C.Staff aired between October 2012 and March 2013. It has been licensed by Sentai Filmworks in North America.