Sector Notes:
Enemy Clusters: Cabal: 4
Material Nodes: Available
Scannable Objects: 2
Partially Inaccessible
Once you feel confident enough to assault a sprawling Cabal spaceport (known as Sunken Isles), this is one of the two Sectors you can use to reach it (the other is Firebase Hades). This Sector is unique in being completely underground. You can access it via the tunnel entrance in the Gulch. Simply head north along the winding tunnel, ignoring the cavern and small interior Cabal base (unless you’re here for collectibles), and maneuver north into a giant cavern with two parallel bridges. The exit to Sunken Isles is on the opposite side of the bridge. The rest of the Tunnels (a series of huge corridors and a landing platform) is only accessible during Campaign Mission: Payback.
Areas of Interest
Tunnel to The Gulch (South)
Head into this tunnel from the Gulch, and check the map. Take this narrow, snaking tunnel with intermittent Sparrow ramps (you can boost off these for fun) all the way into the Bridge Cavern (Area of Interest #6). Exploring the small Cabal base is optional.
Cabal Underground Base
Halfway along the narrow tunnel is a small Cabal base with Legionaries, Psions, and a Centurion to worry about once you pass through into a giant corridor entrance. A huge circular door to the east (indicated by the barrier on the guide map) prevents progress. Stay here for the materials and scannable object.
Wide Tunnel (Inaccessible)
This is inaccessible unless the mission is active. Expect heavy Cabal presence as you drive your tank along here.
Cabal Cavern and Landing Platform (Inaccessible)
This is inaccessible unless the mission is active. An expansive cavern with a large circular landing and loading areas, the place is teeming with Cabals and enemy vehicles.
Rocky Tunnel and Bridge (Inaccessible)
This is inaccessible unless the mission is active. Engage your first enemy tank in this rocky tunnel, then pause to release the bridge controls. This allows access into the Bridge Cavern (mission only).
Bridge Cavern
Accessible at any time, expect the largest Cabal presence here. Outside of the mission, there’s likely to be infantry and a possible Centurion here. The Sparrow helps you easily and quickly negotiate either parallel bridge. Stop to collect materials and scan an object.
Tunnel to Sunken Isles
The exit tunnel leading to and from the main Cabal spaceport known as Sunken Isles, where a gigantic carrier is moored. Remember that you can return from Sunken Isles to the Gulch when you’re traveling in the opposite direction!
Enemy Clusters
Cabal
A small cluster of Legionaries, Psions, and a Phalanx or two guard this base.
Cabal
Additional enemies are in this large corridor cavern with two giant circular doors preventing progress. This dead end has a Centurion to tackle, too.
Cabal
Psions and Legionaries are expected enemies in the northern part of the narrow access tunnel.
Cabal
A Centurion leads the bridge enemies, and the wide expanse of ground makes dropping them from range easier than normal.
Scannable Objects
Campaign Mission
Around half of this Sector is inaccessible unless Campaign Mission: Payback is underway. In that case, you’re trundling through the massive corridors in a Drake tank. This covers Areas of Interest points #3, #4, and #5.