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.

Erthzen is very fond of exploring the depths thoroughly; he leaves no stone unturned and no inch of surface unexplored. Thanks to his habit of eating fishes larger than himself, his body has grown considerably, allowing him to swim faster than the average Deep Sea dragon. He prefers to be alone at all times, but occasionally visits some of his dragon friends or children. Erthzen is a devout father, and even if his offspring are far away, he knows where to find them.