Madarakajin (マダラカジン Madarakajin?, 24): A mosquito monster hailing from Borneo. His plan was to enlist the help of a disgruntled scientist to mass-produce a new type of poison gas. He then tries to assassinate his client who abruptly ends his part of the deal and decides to leave the country. Packed in canisters, Madarakajin targets a nearby amusement park as the ideal location to unleash the poison gas. After seeing most of his canisters destroyed and being discovered by Skyrider he decides to commit a suicide attack. His signature Madaraka Juusei "Mosquito Gun-Shot" is a machine gun attack from his mouth aperture. His right arm is syringe that sprays a flammable green liquid and infects victims with small pox if injected. He can also mass produce Madaraka Ken "Mosquito Sword" that his Ari Commandos can use to fight with. He was grabbed by the scarf and then spun around in a cartwheel leaving him dizzy and vulnerable to Skyrider's signature. Destroyed by Skyrider's Sky Kick.
He was later revived as part of the Second Generation Cyborg Corps (改造人間二世部隊 Kaizō Ningen Nisei Butai?, movie). They were destroyed by the 7 Riders. He was also resurrected as part of Kaijin the Second Generation Corps (怪人二世部隊 Kaijin Nisei Butai?, 27-28). They wore yellow scarves and were destroyed by the 7 Riders.