Dopant activity, founded by Sokichi Narumi who is murdered while he and Shotaro found Philip during an investigation into the Dopants, leaving Shotaro as his successor. The Double Drivers linked, they are used to transfer Philip’s consciousness into Shotaro along with the former’s inserted Gaia Memory. Their catchphrase at the start of a battle is “Now, count your sins! Saa, omae no tsumi o kazoero! Double’s ability to function is dependent on the condition of both Shotaro and Philip, as any disruption physical or mental could affect the Kamen Rider’s mobility or cancel the transformation entirely. Double’s default form using the Cyclone and Joker Memories, the most well-balanced of Double’s usual form with his wind-powered kicks having increased damage and cutting potential.