Sagara Sōzō (相楽 総三?, 1839 - March 26, 1868), real name Kojima Shirō (小島 四郎?), was the commanding officer of the Sekihōtai. After the battle of Toba and Fushimi, in 1868, it constitutes a civilian squad made principally of farmers and merchants. The group promised a reduction in taxes to the people who supported it; when Sagara was asked to return to the headquarters by the Meiji forces, Sagara decided not to because he believed it would be too soon. As a result, the Meiji forces turned on the group, and Sagara, along with seven more leaders, were executed.
Sagara is portrayed in the manga and anime series Rurouni Kenshin, where he is the mentor of Sagara Sanosuke, a fictional character.
The character DJ Sagara of Kamen Rider Gaim is named for Sagara Sōzō. Like Sōzō, he's been secretly fielding the Beat Riders to run his own agenda against the Yggdrasil corporation.