ASCII Media Works
is a Japanese light novel series by Gakuto Mikumo, with illustrations by Nao Watanuki. The novel series began on July 10, 2005, with fourteen volumes currently published by ASCII Media Works under their "Dengeki Bunko" imprint. A manga adaptation by Ryō Akizuki premiered in ASCII Media Works' shōnen manga magazine "Dengeki Daioh" on September 27, 2008, and an anime adaptation began airing in Japan in April 2009.