Hellfish

Among the shouting mountains of the Mismaur Divide one can find one a fish so bizarre and dangerous that has become a part of local religion. The Hellfish or Galimmorth, as it's called by the native Helpharians, dwell in volcanoes for most of their life, swimming through magma as if it were water and nibbling at the outer rock walls.

Flesh of Fire

Mature hellfish bear a rocky armor that grows up to several inches in thickness and shields them from direct contact with the magma surrounding them. Older, larger hellfish have more dense, rugged armor whereas that of younger specimens is more thin and smooth. The rock is not a known mineral though it has a faint luster and a hardness similar to diamond. Whether the fish grow the stone from their body or whether it collects on them is unknown. The armor can be peeled off with a knife or chisel, exposing the tough meat beneath.
Hellfish meat is called muelgalm (literally "fire flesh") and, though inedible, has an unusal ability for retaining heat even long after the creature has died. Muelgalm from freshly killed hellfish retains its heat for typically months and the larger species for years until it begins to fade. The flesh cannot be reheated nor the cooling effect be stalled, however.

Helpharian Folklore

We hunt the Galimmorth not only to sustain our people with the warming flesh but also to sate the anger of the mountains and quiet their fiery shouts. Truly to hunt is the highest honor among the living.

-- From the Helphar Codes

What little is known about the hellfish is about their later stages of life. They spend most of their youth in the bowels of volcanoes, coming to the surface only years later to mate and die. Their lifespan is impossible to gauge though folklore claims they live for hundreds of years. Indeed, most of what is known about the fish stems from the stories and religion of the Helpharians and their Giant ancestors.
Most famous among the stories is the belief that the fish, when too abundant, cause volcanic eruptions. Though it's true that hellfish eat away at the volcanic walls throughout their life, it's unclear the effect this has on volcanic activity. Still, the Helpharians hunt the warming flesh to survive the brutal winters and believe they maintain this invisible balance.

Fuel for the Frozen People

Muelgalm, the heated flesh of the hellfish, is a crucial resource to the helphar cultures who live in near-constant winter. The flesh warms their hearths, cooks their stews, and [??]. Catching the beasts is a monumental effort and is the main profession of some half of the town[??]. Thankfully, a single hellfish provides for months in the heavily-communal villages. Though in the larger cities like Traiberthol, rich estates may boast as many as two or three.