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.

Lumifin is a deep, philosophical dragon. He has a habit of lying on the seabed, staring up at the lighter waters above him, meditating upon the meaning of life and other such philosophical mysteries. He generally snaps at anyone who tries to interrupt his meditations unless it is his mate; she seems to be the only dragon capable of breaking his meditative trance for long enough to hold a non-philosophical conversation with him. On his "off days" when he is too distracted to meditate, he enjoys writing poetry and plays, and engaging in or mediating disputes. He dislikes noise, sudden changes, and deep sea dragons' inability to survive on land. Many water-dwelling dragons look up to him as a leader when they are able to drag him out of his meditations, and he is often relied upon to settle disputes.