The Barbaric Machine Clan Gaiark (蛮機族ガイアーク Bankizoku Gaiāku?, ) are the fictional antagonists from Engine Sentai Go-onger. They are machine-men from the Machine World whose numbers are scattered during their war with the Engines. By the end of the series, only Batcheed, Babatcheed, and Chirakazky remained at large until the events of Shinkenger vs. Go-onger and later in Kaizoku Sentai Gokaiger.
Originally thought to be the last of the Gaiark, the three Pollution Ministers end up on Earth and decide to pollute it to serve as an ideal paradise for them. They based themselves at Hellgailles Palace (ヘルガイユ宮殿 Herugaiyu Kyūden?), located on an isolated island in the middle of the sea. Powering the entire place is the Deus Haguru Magear (デウス・ハグル・マギア Deusu Haguru Magia?), a big gear in their command chamber which is an inexhaustible energy source that Yogostein brought with him from Machine World. The gear's power is used Yogoshimacritein to create an army of Barbaric Dohma until the primary Go-ongers break it, causing Hellgailles Palace to self-destruct and sink into the sea. During the events of Samurai Sentai Shinkenger vs. Go-onger: GinmakuBang!!, though revived, the Pollution Ministers want nothing to do with Batcheed's plan and spend their time at Genta's Gold Zushi stand before running off back into bottom of the Sanzu River. The Ministers also make an appearance in the Kaizoku Sentai Gokaiger vs. Space Sheriff Gavan: The Movie as captives in the Makuu Prison for giving up their lives of villainy before being released by the Gokaigers.