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.

Taluis is a sadistic Cavern Lurker and the Tyr, or leader, of the tribe of Cavern Lurkers in the territory, numbering eleven. Having forged a pact with Aszalia'xai, the ruling Vampire dragon, Taluis and his tribe act as the eyes and ears of the Vampire dragons due to their abilities in stealth, in return for free rein hunting the dragons Aszalia'xai finds to be expendable- often going for younger Nebulas, who seem to be the forefront of the resistance against the Vampire dragons. Taluis is the first to be hatched by Kiryu without acknowledging him as master: the human's submission to Aszalia'xai put the latter in a dominant position, in Taluis's eyes. As such, Taluis treats Kiryu with contempt and aids to keep him in constant fear of his life.