Medusa (4, 21, 27, Movie) - A Medusa monster who has ability to fly, summoning snakes and turn human into stone with her eyes. She takes identity as Professor Kogure Seijiro assistant's named Kiyomi. Destroyed by X's X Kick.
Apollo Geist's Last General Attack!!
Medusa have revived with other Kaijins, to support Apollo Geist, & defeated by Kamen Rider X again.
Special Edition, Full Force of Five Riders!!
Medusa have revived again with other Shinwakaijins & defeted by five riders.