Kamen Rider Sangou is a fictional character from the Kamen Rider franchise, first appearing in the movie 'Super Hero Taisen GP: Kamen Rider 3.' He is introduced as an alternate history version of a Kamen Rider created by Shocker, an evil organization. Sangou is initially portrayed as an antagonist who opposes the original Kamen Riders, but his sense of justice eventually emerges. His conflicted nature and impressive combat skills make him a complex and memorable character in the series.