Savage Water Bankiju (Barbaric Machine Beasts)
The Barbaric Machine Beasts are monsters created to pollute the Earth. They are each separated into three sects, that are under the Pollution Ministers: Savage Ground, Savage Water, and Savage Sky. The Barbaric Machine Beasts are each upgraded with a special energy that enlarges them upon being defeated in battle, though the process is slightly delayed.

Pipe Banki
Height: 220 cm to 55 m
Weight: 247 kg to 617.5 t
Savage Water Barbaric Machine Beast sent by Kegalesia. He is sent to pollute a dam, but is defeated by the Go-ongers. He then returns later to pollute the river in giant form, attacking the Go-ongers when he learned they didn't have their Engine Casts. They tried using their Highway Buster on him but it was no use. The three got their casts back and challenged Pipe Banki with EngineOh. He breaks a bridge where there is ongoing traffic, so EngineOh bridged the gape and the cars went over the robot. Unfortunately Pipe Banki didn't make it easy and knocked EngineOh off and caused one car to almost tetter off. Go-On Black and Go-On Green luckily saved the occupents of the car and Engine-Oh was able to destroy Pipe Banki, causing bubbles to emerge. Kegalesia was rather livid over his defeat.

Spray Banki
Height: 192 cm to 48 m
Weight: 216 kg to 540 t
A clumsy Savage Water Barbaric Machine Beast sent by Kegalesia to steal the Engine Cast of Birca. He can shoot acid from his mouth, which he does after counting to three. Kegalesia called spray Banki her own child. Kegalesia first showed herself to the others along with her beast. He was wounded by Birca and Gunpherd before Engine Oh destroyed him.

Bombe Banki
Height: 209 cm to 52.2 m
Weight: 235 kg to 587.5 tons
A gas cylinder Savage Water Barbaric Machine Beast sent by Kegalesia, who fed lies for him to tell the Go-Onger. He could make any metal rust, including the main three Engines. Carry Gator was chasing after him and he made the Go-Onger believe he was an enemy. Bombe Banki was destroyed by the newly formed GunBirOh. Speedor, Bus-On, and BearRV remain rusted after he is gone.

Hikigane Banki
Height: 213 cm to 53.2 m
Weight: 263 kg to 657.5 t
A trigger Savage Water Barbaric Machine Beast under Kegalesia, ranked as Gaiark's top sniper. He was sent to return Bukorin, Renn's new friend, to her father Gego. He called Gego 'Boss' and looked up to him. Hikigane was attacking randomly in Tokyo Tower, Gego told him not to attack strangers, but only his enemies. Using his various attacks, like "Water Magnum", Hikigane Banki overpowers the Go-ongers until Renn arrives to defeat him. He is destroyed by Engine-Oh G6, with his only regret not to see the Chunichi Dragons' winning streak one last time.

Kama Banki
Height: 218 cm to 54.5 m
Weight: 270 kg to 675 t
He is a bath heater Savage Water Barbaric Machine Beast sent by Kegalesia, says 'Come On' in his sentences. Using a pink mist from his nostrils, Kama Banki teleports people into the hotsprings on his head where their cares are steamed away. In doing so, he is removing any interference in Gaiark's plan--which is humanity. A dojo owner is able to beat him, so Kegalesia goes to learn his secret. She tells Kama to stand under a waterfall and he reaches enlightenment in doing so. His power reaches zenith but he is defeated by a love-filled Hanto and Engine-Oh G6 with the wrong souls in different casts.

Oil Banki
Height: 210 cm to 52.5 m to 55.1 m (with wings)
Weight: 236 kg to 619.5 t to 619.5 t (with wings)
Kegalesia's Oil Savage Water Barbaric Machine Beast who can create a really slippery oil slick on the city, incapacitating not only normal ground vehicles but also Engine-Oh G6. After being defeated by Toripter and Jetras, Hiramechimedes asks if he can take over Oil Banki, which Kegaleshia refuses to. Hiramechimedes upgrades Oil Banki, but he seemingly has no change. When in battle, Hiramechimedes grants wings to Oil Banki to fight the Wing Engines. But using mops to counter the oil slick, Engine-Oh and GunBir-Oh destroy Oil Banki.

Manhole Banki
Height: 219 cm to 54.7 m
Weight: 246 kg to 615 t
A Savage Water Barbaric Machine Beast sent kidnap people that can spin ballpens as part of the Gaiark's place to power a machine to destroy the world. The Go-onger disguised to lure him. His signature move is "Grind Manhole", shooting out manholes at his enemies. He was eventually destroyed by Engine-Oh G9.

Straw Banki
Height: 216 cm to 53.8 m
Weight: 230 kg to 575 t
A straw Savage Water Barbaric Machine Beast, his Straw Scatter Shot to have people breathe out poison gases. He drinks from four bottles to gain a special ability. Explosive Drink (yellow) lets him to shoot bubbles that explode on impact. Smokescreen Drink (purple) releases a smoke screen, and his Capsule Drink (blue) creates a bubble prison. Kegalesia created the special Gai Aqua (red) to increase his evil. He looses it and it effects Sosuke and Renn but Kegalesia creates a supply of it for him. Straw Banki is defeated by Sosuke and Speedor inside of Go-Roader before growing huge and scrapped by Bearrv, Bus-on, Seiku-Oh, and GunBir-Oh.

Shower Banki
Height: 210 cm to 52.5 m
Weight: 224 kg to 560 t
A shower Savage Water Barbaric Machine Beast who ends her sentences with the word "Shower" in English. Kegalesia gave her special liquids to freeze and melt everything around her. However, the liquid has a unforseen side effect that freezes any male exposed to it, within 30 mintues. Once aware of this, Kegalesia sends Shower Banki to eliminate the male Go-ongers. However, Saki, Miu, and Bearrv managed to outwit and best her. By the time she grows, the male Go-ongers arrive and GunBir-Oh Jetras and Seiku-Oh Gunpherd destroys her.

Bin Banki / Mahobin Banki
Height: 214 cm to 224 cm to 56 m
Weight: 229 kg to 240 kg to 600 t
A bottle Savage Water Barbaric Machine Beast. Kegalesia uses Manabu Yushima's magic and upgrades him into the stronger vacuum flask-based Mahobin Banki. He is destroyed by Kyoretsu-Oh.