Deep Sea Dragons, as their name suggests, spend most of their time in the darkest depths of the sea. They have a bioluminescent dorsal spine that serves to attract prey and communicate with their own kind. As with many deep sea animals, they generally eat whatever they can manage to bait. They rarely leave the ocean floor, surfacing only during breeding season. When they do choose to travel to the shallower depths, they avoid bright lights and will only come up far away from shore.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Many years ago, a fisherman on the tribal islands dotted out in the ocean, headed out to the deeper reaches of the ocean in order to score a large catch. What happened next was pieced together by the people that found him on the beach, a gibbering madman. Unbeknown to the fisherman, it was breeding season for deep-sea dragons and as he sailed into the deep sea, one had reared up in front of him, smashing the boat and casting him into the depths. His survival a miracle, the fisherman, and every fishing family in the tribe since, has headed out to the deepest sea every few months and dropped offerings of food to the depths to appease "The Undershadow".