The Robot Fortress is a building complex that covers the southern half of the Sentai Mountain. It is heavily guarded, but Humans have been sent into the fortress occasionally. However, there is still very little known about the robot's vast base.
- The Head - The newest part of the structure, shaped like a robot head and connecting to the Goldstone Bridge. It was created by the remote input of a captured code brick. From its shape, this segment seems to have been created by a magnetic field.
- Labs - Design and test areas for the Robot Battle Machines.
- Assembly Line - Where robots and battle machines are constructed.
- Storage Facility - Where robots that haven't been programmed are kept.
- Programming Complex - Where newly constructed robots are programmed for battle.
- Prisons - Cells where captured humans are kept.
- The Mines - Ryo once visited the mines on the robot side of the mountain. They were empty, as they were deemed too troublesome to build on. A refugee was hiding in the mine.
|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|