Kōichi Sakaguchi (坂口 候一 Sakaguchi Kōichi) is a voice actor who had portrayed multiple monsters in the Kamen Rider franchise. His most notable appearance is as the voice of Zu-Gumun-Ba, the very first monster of the Heisei Kamen Rider revival, in the opening episode of Kamen Rider Kuuga. He also has voiced the Claw-Hand Mole Imagin in Kamen Rider Den-O and Knife Gamma in Kamen Rider Ghost.