Kamen Rider ZX Birth of the 10th Kamen Riders All Together (Jugo tanjo Kamen Raida zenin shugo)

Ryo Murasame is an aircraft pilot. One day he is taking his sister out on a ride along the Amazon when they are shot down by a UFO. They survive only to be captured by the Badan Empire. His sister is killed, while Ryo becomes the Combat Roid known as ZX. His memory is erased by the Badan Empire, and he works as their agent of evil.