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.

Aruin'mull lives in DeepReach, a great trench in the southern sea that harbors a lot of wildlife. He has lived there since he matured into his adult state. Many of the other Deep Sea Dragons consider him to be a hermit, and very shy. He will hunt when everyone else is inactive, and even when mating season comes along he is still seen in his underwater alcove. But most recently a female has caught his eye, which lures him out to interact more and find out who she is.