The Sigma Depression is more appropriately called Chaos Sigma. It is an equatorial zone to the west of the Cat's Eye Trench, a depression in the highlands that almost (but not quite) connects to the Gengi Trench, a subsystem of the Cat's Eye. A monorail stretches right through the Sigma Depression from this point with only one stop - this is the only major transportation through the region beyond the Liberati caravans.
The landscape of the Sigma Depression can quite appropriately be called tortured. The geological event which formed the Trench sent massive compression waves into this region, combined with already active vulcanology to make some of them most convolute landscape on the planet. Massive deposits of iron, nitrogen-bearing minerals, phosphorus and magnesium make this a very mineralogically rich zone, while at the same time due to its twisted deposition the usual gravitational and mass-detection sensor systems are virtually useless here from the presence of these formations.
There are literally thousands of landmarks and interesting features within the region, most of them uncharted by the Capricians and only known through experience by the Liberati. Historians compare this region to the historical region of Afghanistan on Earth - Impossible to properly control, and untenable to attack.
- Hakkar maintains a large refinery within the Sigma Depression. This, along with a junction station, forms the only stop on the monorail line that splits the Sigma Depression in half. This refinery is where the Liberati that live in the region often sell their mined wares, or where Corporate mining sites will lease time in the smelter instead of shipping raw ore back to Gomorrah.
- The Van Saar maintain ten large facilities within the region, each of them holding enough supplies for nearly a year's worth of living. These supplies are hidden in storehouses throughout the area around the homesteads, as they are never occupied for longer than a few months at a time.
- The Ansalle also operate heavily in this region, often acting as go-betweens for the Van Saar and contacts in Gomorrah.
- There are dozens of bolt-holes throughout the region, set up and operated by the Van Saar. Each one has enough supplies for a group of twelve men to survive comfortably for two weeks, as well as giving them a Reubeni trike and radio.
- The CEF once operated three fire bases wtihin the Sigma Depression. Activities of Black Talon 05 destroyed these bases, and it is questionable whether they have been re-established.