Onmyō Taisenki (陰陽大戦記) is a Japanese mixed-media project developed by WiZ [ja] and Bandai.

A manga series, scripted by Yoshihiko Tomizawa and illustrated by Hiroyuki Kaidō, was serialized in Shueisha's V Jump magazine from November 2003 to December 2005, with its chapters collected in three tankōbon volumes.

Riku comes to the scene and that's where he first gets in contact with his Drive (神操機), the device he uses to call and make a 'contract' (契約, keiyaku) with Kogenta of the Byakko, his shikigami and, from that day on, best friend.

the 'Four Great Heavens'), and freeing Utsuho (ウツホ), a boy who was born with the power to control yōkai (妖怪), and had been imprisoned for thousands of years.

A manga series, written by Yoshihiko Tomizawa and illustrated by Hiroyuki Kaidō, was serialized in Shueisha's V Jump from November 19, 2003,[a] to December 17, 2005.