Krell

Deepwater Krell

The Deepwater Krell do not generally trust outsiders, and outside of Abyssal zealots, are reluctant to leave Trith. Initially separating from the Greenback Krell over two million years ago, the Deepwater Krell are larger than both the Greenback and Tidal Krell. The Deepwater Krell have comparatively larger eyes, more powerful but less dexterous claws, and darker colouration. They are not outright hostile towards other races, but prefer to be left alone. Deepwater and Greenback Krell are genetically similar, and are inter-fertile - although cross-breeding rarely occurs.
sustenance
There is little intermingling between the Deepwater and Greenback Krell, only reliably coming into contact with each other once at the beginning and end of every Vool Cycle, at the Reef. Nonetheless, the Deepwater Krell play an important role in the Prosperous Shoal - it was they who first discovered the power of the boilers, creating ceramic. Frequently coming into contact with the boilers, it continues to be the Deepwater Krell who produce the most "boiled" objects. 
The Krell religion, Abyssism, also has its roots in the Deepwater Krell. The belief system of this religion is relatively simple - that the universe as a whole is a tremendous ocean, with stars and other heavy astronomical objects being gravitational "islands". Abyssism is a common belief throughout the Prosperous Shoal, and even outside it, although it is the Deepwater Krell who take the religion to fanatical levels. 
Most outsiders to the Prosperous Shoal will encounter Deepwater Krell before they encounter any of the other subspecies, typically at rest-stops many systems from the Prosperous Shoal. Their interpretation of their religion drives them to seek out and chart "the galactic deep", and render it safe, travelling out into the void and slaying the void creatures that live there. While they are tremendously skilled at doing this, the sheer scale of the void means that they are effectively changing nothing.
sceptical