?) is a Japanese light novel series by Katsumi Nishino, with illustrations by Koin. The first novel was released on October 31, 2005, and as of February 25, 2008, nine volumes have been published by Media Factory under their MF Bunko J
label. A manga adaptation by Rin Yamaki started serialization in the seinen manga magazine Monthly Comic Alive
on June 27, 2006, also published by Media Factory. A drama CD was produced by Media Factory that was released on March 28, 2007. An anime first aired in Japan on April 5, 2008 and is produced by Xebec. A visual novel named Kanokon Esuii
developed by 5pb. was released for the PlayStation 2 on July 31, 2008.