A 2006-2017 manga by Takenashi Eri, serialized in Ichijinsha's Comic Rex, also adapted into a 2008 anime and 2009 OVA by A-1 Pictures, and a 2008 light novel written by Takei Touka, with illustrations by Takenashi and Kirino Kasumu. Furthermore in 2010 the series received a spinoff manga titled Kanpachi by Takenashi Eri and Yuuki Shin'ichi (Takenashi's brother) titled Kanpachi.
