Series: Kamen Rider X
The mentor of the previous Kamen Riders.
Keisuke's fiancee, Keitaro's assistant, and a G.O.D. member. She is an Interpol investigator and executes undercover operation in the G.O.D. She became a cyborg by G.O.D.'s operation. Her true identity was exposed protecting a child from Strong Arms Atlas and she was destroyed by the General of G.O.D.
Ryoko's twin sister who is an Interpol investigator. She died protecting Keisuke from Strong Arms Atlas's arrow.
A student of Johoku University and Tobei's coffee shop worker.
Chiko's friend and Tobei's coffee shop worker.
Keisuke's father, Keitaro was a robotics genius whose technology attracted G.O.D.'s attention. As a result, Keitaro died saving his son's life at the cost of his own.