Yuji Toba (鳥羽 祐二,Toba Yūji): Souta's ex-partner from his times as a spy, kidnaping him in order to know the place where SGS kept the Imperial Pearl and steal it for the country. It's later revealed that he recruited the Questers to help him. Rei would forcefully extract from Souta's memory the location of the building so they could steal the Precious and Toba would receive the Imperial Pearl as payment. However, Yuji soon got a change of heart after hearing's Souta intend to make up for his crime. When the Questers finally locate the building and try to break into it with Quester Robo Turbo, Toba detonated a bomb he installed in the cockpit previously, giving SirenBuilder and Ultimate DaiBouken the chance to destroy the robot. He called the act a "parting gift" to Souta. Portrayed by Akira Kubodera (窪寺 昭,Kubodera Akira), who previously portrayed Kanai (Giraffa Undead) in Kamen Rider Blade and Kunzite in Pretty Guardian Sailor Moon.