|This article is about a/an villain group in J.A.K.Q. Dengekitai.|
Crime Big Four (クライム四天王 Kuraimu Shiten'ō) - A quartet of ruthless mercenaries and despots who joined forces with Iron Claw to wreak havoc across the globe. The Big Four’s headquarters was a gigantic flying saucer (UFO) which could fly undetected around the world. The various Big Four commanded their own armies of followers including remnants of the splintered “Black Cross” army that battled Go-Ranger. In fact, Goranger member Peggy Matsuyama had been tracking the whereabouts of the villains for a while. The Big Four had battled with other Toei heroes across the globe including Kikaider along with Kamen Riders V3 and Amazon. Facing the JAKQ and Goranger teams, the Big Four combine into the super cyborg entity “Big Four Robo”, a monstrous and hulking mechanical monster with multiple cannons protruding throughout his body and a grinder in his lower torso. Virtually invincible, it took the combined special attacks of JAKQ's Big Bomber and Goranger's Goranger Hurricane Ball to destroy the monster.
- Baron Iron Mask (鉄面男爵 Tetsu Men Danshaku) - An iron masked despot who had been terrorizing the European continent. Fought Kamen Rider V3 offscreen. Leads his own specialized troopers he calls his “Tetsu Men Gundan” (Iron Mask Battalion). Carries a heavy iron shield and battle spear which he can hurl with devastating skill. Also carries a blowgun which he can use to fire poison darts.
- General Sahara (サハラ将軍 Sahara Shōgun) - African conqueror who once battled the Gorengers in Africa with his Sahara Battalion. A master swordsman and strategist, he is both ruthless and cruel in battle.
- Captain UFO (UFO船長 Yūfo Senchō) - Fought Kamen Rider Amazon offscreen. While comical looking, Captain UFO is none-the-less a brilliant criminal mastermind who commands the UFO command ship that the Shi Ten Oh use to travel the world.
- Hell Boxer (地獄拳士 Jigoku Kenshi) - A terrifying tyrant from Mongolia who uses his hideous skull adorned armor to strike fear in his foes. Fought Kikaider offscreen. A savage and fierce warrior, he wields an iron ball and chain to crush and kill his opponents.