小野大輔
An anime adaptation produced by Bee Train, written by Hiroyuki Kawasaki, and directed by Tomoyuki Kurokawa began airing in Japan on October 3, 2010. Minako Shiba designed the characters and Daisuke Ono and Ayumi Fujimura were cast as the lead roles, with the opening theme songs also performed by Ono. The songs, "Key," "Key Phase 2," and "Key Phase 3," were released on November 17, 2010. The series has been licensed for digital and home video release by Sentai Filmworks.