On the water-planet of Ashtoreth, Sinaian and Abaddonian explorers through the Gateway have encountered a species of "mer-cats" -- feline-like sapients with lower bodies resembling those of porpoises or dolphins, with sleek and streamlined bodies and stringy "head hair" (sometimes shaved off -- in the case of warriors -- for less resistance when going through the water). They come in a wide variety of colors, marked with tiger stripes, spots, rosettes and other traditional "wild cat" markings, and a few more bizarre examples.

Mariners have their own language that has some similarities in structure and word choices to Khattan, though many Mariner words are unpronuncable by most off-worlders. (Eeee can make a fairly close approximation, though.) In the years since initial contact with this species, many Mariners from a region known as the Abyss have learned to speak Khattan and Bosch, though only a few know Rephidim Standard or other Sinaian languages. (These particular Mariners are known as "Abyssinian Mariners" or just "Abyssinians".)

Mariners are mammals with considerable lung capacity, living near the few islands that dot the surface of Ashtoreth's planet-covering ocean, or else living in underwater areas that -- for one reason or another -- have oxygen supplies.