Leviathan

Leviathans are great monstrosities lurking in the depths of the southern seas. They are the primary cause of the lack of exploration to the south. Adverse to light they stay in the dark depths until sunset before rising to feed. Leviathans are of a size with large whales ranging from 60 to 200 feet long and weighing between 200,000 and 500,000 pounds. Leviathans are cannibalistic in nature and can be lured by the bloody flesh of their kin. The few who are daring enough to hunt them use great hooks baited with leviathan flesh, to lure the creature. Then when it gets close to the surface they flash great lights at the monster to blind, weaken, and confuse it. More barbed hooks are thrown, all with leviathan bone cores, hooking the creatures armor plates and stopping it from fleeing to the depths. It is a constant battle keeping the leviathan above or near the surface until sunrise when the sunlight streams through the water killing the creature. The corpse is then hauled back, usually to Solan for processing. Some of the meat is used for future hunts, the blood is refined into plasm, the bones are cleaned and used for magical items and new hooks, the armor plates are pried off and attached to ships, and the rest of it is melted down into a chemical sludge known as Slurry or "Slag" which is discarded.
Leviathans come in all shapes and sizes. Some have tentacles, others have fins, some glide through the water like manta rays. Many but not all are covered in armor plates that are harder than steel. The typical leviathan looks like an armored whale with a gaping maw filled with teeth. Their blood and flesh are both dark blue, almost black.