Mariners are "mer-cats" native to the planet of Ashtoreth, appearing as strange hybrids of Khatta and some sort of seafaring mammal. The upper torso, head and arms of a Mariner resemble that of a Khatta, though with very fine, thin fur in a number of strange colors (not restricted to traditional cat coloration) and patterns (stripes, spots, patches, tearmarks, etc.). The lower body of a Mariner resembles the tail of a dolphin or porpoise. Mariners have head hair, though many of the male warriors shave their hair for less resistance when swimming through the water. They have two pairs of eyelids, one pair being translucent to protect the eyes while underwater. They are warm-blooded mammals, though external gender features are subdued or concealed, as their bodies are very streamlined. Their hands end in short claws, and are webbed. Mariners are omnivores, feeding primarily on fish.
Most Mariners are air-breathers, but have an enormous lung capacity, and also a limited ability to "recycle" oxygen, thus extending their underwater capacity even further. The Sirens (a Mariner sub-type) are amphibious, however, able to breathe air or water with equal ease.
Sirens differ in appearance from Mariners in that they are even more sleek, even fragile-looking, and have translucent, multi-colored membranes that radiate from their torsos, illuminated with traces of pulsating light, giving an appearance of wearing a gown or a robe.
Abyssinian Mariners, with whom Sinaian and Abaddonian explorers have made contact, may be familiar with the languages of Khattan or Bosch, and less likely Rephidim Standard.
Note: Mariners are naturally born to the water, rather than the land. In oceanic environments, they're natural-born swimmers, and are perfectly at home, while normal land-dwelling PCs would be trying not to drown, or having to ride along in some sort of submersible. On the flip side, a Mariner would be greatly hindered in interacting with others on land. "Light RP" in Rephidim would probably require the Mariner being carted around in a water tank. (Not very convenient or likely.) A character of this sort, therefore, would be very specialized for a particular environment, and this is not reflected in terms of Disadvantage points. It's simply a trade-off.
PC Requirements (Abyssinian):
PC Requirements (Siren):