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.

Under Deep Rock comes from an ancient colony of deep sea dragons, and was named according to their customs. He lives in a system of undersea caverns which branches out beneath Koreth's cave, rarely coming to the surface. Occasionally he will speak to the land dragons, but he has a limited understanding of surface customs and has no great desire to learn more. He feels that the surface is inferior in all ways to his home realm. Many perceive him as bigoted, but this is difficult to verify, as he is nearly impossible to talk to, with his avoidance of surface-dwellers and indecipherable communication; his telepathy is slow and choppy. In fact, no one knows very much about him.