|This article is about a/an kaijin in Kamen Rider Black RX.|
A one-horned bluish imp monster armed with a pitchfork. He can shoot a beam from its horn. Maribaron planted him inside Kohtaro to kill him when he was being pursued by the police. This was a plan by Maribaron to hack into the city records and make specific people look like criminals. When Kohtaro found out about Wilki while he was in jail, he transformed into Kamen Rider Black RX and escaped from his cell. Wilki even poked him while he was escaping on Acrobatter. While in the sewers, Kamen Rider Black RX became Bio Rider and found out what the Crisis Empire was up to. When the next person was arrested, Wilki attacked Kamen Rider Black RX and attempted to deliver the final blow. Kamen Rider Black RX faked his death and was brought to Maribaron. He eventually became Bio Rider right as Maribaron was about to destroy him. Bio Rider revealed that his form prevented Wilki from killing him. With all the police computers experiencing a system down after Kohtaro destroyed the false records, Maribaron retreated and Wilki attacked. Bio Rider called out his Bio Blade and fought Wilki and the Chaps. Bio Rider managed to chop off its horn and destroy its pitchfork. Bio Rider then reverted to Kamen Rider Black RX and brought out his Revolcane to disarm Wilki and destroy him.