Cavern Lurker Dragons are nocturnal ambush predators. Although small, they are very aggressive and will attack anything weak enough to be overpowered. Their preferred method of hunting is to lie in wait in a cave, burrow, or other small, enclosed space; when any potential prey passes they will lunge out to grab hold of the unsuspecting victim and drag it back into the lair. Cavern Lurkers have an odd aversion to sunlight and almost never venture out during the day. More commonly sighted are the odd piles of bones they stack near the entrance to their dens. Their mating call is a low-pitched bumping noise.

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.

Arius has come to one conclusion over the course of many years; only the intelligent will survive. This has become a very dangerous aspect of him, as he "punishes" those who fail to meet his standards. Many consider themselves lucky that Arius is nocturnal, as most dragons are tucked away, sleeping at that point. Those that are unlucky enough to be awake during the night try to avoid him like the plague, ushering away the young ones and hiding in the shadows when he passes. When curious hatchlings ask questions, they are told this story: Once, long ago, a rather intelligent White hatchling was so unfortunate as to bump into the Cavern Lurker, and the dark dragon asked it, what it believed, were simply questions, seeing just how intelligent the feathered dragon was. This went on for hours, until finally, the white hatchling stuttered, and answered incorrectly. In a flash the Cavern Lurker's jaws came down on the hatchling, and the only evidence left was a single white feather.