Polop, the Sea Kings

The “seamaws” or “fish devils” are never found far from water. A Polop can usually breathe air for as much as a day, but dry climates and extended periods outside of water or away from their life-support equipment doom them to a suffocating death. Most appear as horse-sized, vaguely sexapedal shapes with glabrous, scaled skin, huge, unblinking eyes and a maw of fanged teeth. Their body plan involves six clusters of locomotive and manipulatory appendages evenly paired along either side of their body, each cluster consisting of two to four crab-like legs that end in small “hands” of curved chitinous material. Flexing these limbs and the thin integument between them propels them rapidly underwater, while land movement leaves them in a vaguely centauroid posture, leaving two clusters free to manipulate tools. The Polop are the unquestioned rulers of the Carceral Sea around the Gyre. Coastal raids by Polop harvesters are a commonplace, and every fisherman knows to sail only in daylight hours, when the fish devils are quiet. Even so, colonies of Polop have been found in the Blind Marsh, the Mirewash and the Tombwater, with some reported around the Font. Even the Usuldarum and Usulmot rivers have known local infestations of them.
The Polop eat humans. As far as scholars can understand, they find humans to be delicious, but the act of eating them is some sort of religious or philosophical statement of species superiority. “We Who Eat” is the Polop term for themselves, and it’s true that Polop biology appears capable of consuming almost any living creature without ill effects. Some Polop trench-cities contain extensive human breeding pens where captive populations are raised as meat stock. Most humans, however, are eaten shortly after they are taken back to the city. While Polop will eat dead flesh, they find it more satisfying to consume sentient creatures aware of their fate.
Polop magic and technology are sophisticated in matters of life support, live-coral construction and the mental domination of monstrous sea life, but their underwater existence leaves them with few high-temperature or high-energy resources. Their great trench-cities are built in the lightless depths, illuminated by phosphorescent masses, while colonies nearer the surface are fabricated of bubbles of pressure-tight coral lattices.