The Eastern Trench or Dark Depths is a location in the DLC: The Center that was added as a small trench in the southeast in PC patch 245.0 and later expanded in PC patch 257.0.
The Eastern Trench is located along the entire eastern edge of the map. This is a very dangerous place to venture as visibility is near-zero and pitch-black. Large, dangerous creatures lurk in its dark depths.
The Artifact of the Brute is located within a small cave along the southern portion of the trench. Resource-wise, Oil and Silica Pearls can be found dotting dark deep and bio-luminescent cliffs. Small Obsidian deposits also line the volcanic rifts at the seafloor.
Unlike most other maps, use of a Gas Mask or full tek suit does not make the water clear anywhere on The Center. Keep this in mind, because without changing ini settings or mods your visibilty will be mediocre at best.
You cannot normally touch the lava in the volcanic rifts, removing the possibility for an accidental death. (It might still be possible, needs further testing)