Enemy, and later ally, ofKamen Rider V3. Also known as the "Avenging Demon". A former scientist of the Destron organization framed as a traitor, Jouji Yuki takes up the name of Riderman to eliminate V3 and clear his name. Riderman is not named the 4th Kamen Rider untilhe sacrifices himself to redirect a missile bound for Tokyo. His distinguishing features include his mechanical right arm and helmet that exposes the lower half of his face.