Croyzel is an insectoid-like robotic monster that can manipulate heat by harnessing it from the sun. Crisis Empire used it to induce a heat wave in the city with an artificial sun. He was sent alongside the Chaps and the Skullmastars to obtain a scientist. Kohtaro henshined into Kamen Rider Black RX and battled Croyzel. When his children where captured, the scientist tried to fight Croyzel with a laser that would counter his abilities. Kamen Rider Black RX showed up just in time and freed his kids. When Croyzel injured the scientist, Kamen Rider Black RX became Robo Rider and engaged Croyzel while the scientist's daughter brought the laser to her father and used it on the artificial sun. Robo Rider destroyed Croyzel with his Vortech Shooter and the artificial sun was destroyed with the robot.