Uni Demon (ウニデーモン Unidēmon?, 39-40): A sea urchin monster. His plan is to convert middle age mothers into a female oni army (on a supplementary side they serve as his personal brothel crew). His first attack was a cabaret troupe on a cruise liner. He uses one of the dancers to lure Tsukuba Hiroshi in a trap and captures him. Apart from his "Oni-Ray" (fired from the red crest on his head) that converts women to oni monsters, his spiky body makes physical attacks useless, and he wields a giant/long spiked club. Any impact causes massive damage and explosions. Destroyed by Kamen Rider 2's Rider Kick.