Kamen Rider 10's Birth! Riders Unite!

Ryo Murasame is an aircraft pilot, one day he was taking his sister out on a ride along the Amazon when they were shot down by an UFO. They survived, captured by the Badan Empire with his sister killed while Ryo became the Combat Roid known as ZX. His memory is erased by the Badan Empire and worked as their agent of evil. This does not last long as an accident occurs which causes Ryo to regain his memory and escapes Badan. (Wikipedia)