Sentai Fortress was built after Sentai Mountain split in two. It was connected to many bridges that spanned the chasm. Its main gate was connected to the Tenchii Bridge.
At one point, the robots sent over the Striking Venom along with an army of robot battle machines to conquer or destroy the fortress. The humans were desperate, and didn't know what to do, and the Striking Venom was closing in. Due to the thinking of Takeshi, the base was safed when he defeated the Striking Venom, forcing it and the army of robots to retreat.
The humans had won, but despite the victory, the base was too heavily damaged to stand. Keiken revealed information about the Golden City, and sent Takeshi, Hikaru, and Ryo to find it. They did, and the Sentai Fortress’s inhabitants fled there.
Later, Takeshi, Ryo, Ha-Ya-To and Hikaru were sent to retreive a disk from the ruined base, and found it overrun by the robots. Ryo then realised that the mission was a distraction, and turned back to the Golden City. There the team found a doppelganger of Sensei Keiken (Meca One), who had destroyed the city’s jamming device.
The Fortress is currently vacant and damaged beyond repair.
- Hangars: where Battle machines were fueled and repaired.
- Labs: where pilots learned about computer technology, energy and elcetronics.
- Dormitories: where pilots lived and slept. It had a rec area, cafeteria, study areas and much more.
- Training Grounds: where pilots trained and learned tactics and skills for piloting the various battle machines.
- Infirmary: where pilots that have been injured go to be healed.
- Monorails: used as transport between upper sections and mobility for turrets. Mounted on walls.
- The Sentai Fortress was released as a large, boxed set in 2006 in the second wave of sets. It is the largest Exo-Force set ever produced.
- It included a system-built fortress, which had a main gate, a hangar, an armed control tower, a medical tower and walls to connect them.
- The front walls were armed with turrets, while the rear ones had transport trollies.
- It also included the Silent Strike battle machine, and Meca One's personal battle machine, (later dubbed the Venom One) a Venom Walker, two Iron Drones, and Takeshi, Ryo, Hikaru, Ha-Ya-To, Sensei Keiken and Meca One minifigures.
- Its set number was 7709.
- Price: $100
|Northern Half:||Sentai Fortress (Ryo's Labs) (Sentai Village) (Sentai Gate) | Sentai Golden City (Golden Tower) (Nightmare Lab) | Abandoned Village (Generator Room)|
|Southern Half:||Robot Fortress (Robot Construction Labs)|
|Both Halves:||Bridges (Tenchi) (Mechara) (Cyrid) (Goldstone) | Gates (Sentai Gate) | Mines|
|Other Places:||The Gorge | Deep Jungle | Fields|