doa is a Japanese hard rock band currently under the Giza Studio label. The band is named after a single letter of each of the members' names: Daiki Yoshimoto, Shinichiro Ohta, and Akihito Tokunaga. Two of the band's singles, "Eiyuu" and "Aoi Kajitsu", were used as opening theme songs for the 2004-2005 tokusatsu TV series Ultraman Nexus. Shiro no Jumon was used as an ending theme song for Saiyuki Reload Gunlock.