The Deeps

You are all fools to journey into The Deeps. The only thing you'll find down there is your death in the jaws of the Leviathan. 

The Deeps are the areas of Retika's extensive oceans that cannot support Seadweller life.  The temperatures are cold, the light from Retika's home star doesn't reach, and the pressure is immense.  Even the so called Deep Seadwellers did not live at these depths. 
Despite all of this, life does exist in the Deeps.  The most famous is the Mecshate, or Leviathan, a predator the size of the humpback whale on Earth, that swims in the deep open waters, feeding on anything that is unfortunate enough to wander into its territory.  Geothermal vents provide some pockets of heat that allow some forms of coral to grow, providing shelter to the scavenging crustaceans that skitter along the ocean floor, feeding on the carcasses of other sea life that live in the warmer, shallower, well-lit waters.
Retikan Seadwellers are often raised with a healthy respect, bordering on fear, for the Deeps, and only the bravest of souls even suggest scientific expeditions into them.  Itakian researchers, who originally had no such fear, soon developed one when their teams, protected in pressurized and armored submarines, never returned.
Despite the combined cultures making into to space and joining the galactic community, very little is known about the Deeps.  And with the danger of exploring it being so high, it is likely that the Deeps will always be shrouded in mystery.

Geography

The Deeps encompass a very large area of Retika's crust, from vast abyssal plains to massive trenches to volcanic seamount ranges.     Most of the deeps consist of abyssal plains, hills, and valleys, but near tectonic fault lines, more trenches and seamount ranges can be found.

Type

Ocean

Location under

Retika