Ryoko Mizuki (水城 涼子 Mizuki Ryōko): 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.