Hellfire Wyverns are so named for their foul tempers and fiery visages. Their social structure places all females above all males, due to superior physical characteristics and violent dispositions. Forced subservience of the males causes them to become vicious, petty, antisocial, and passive-aggressive compared to the aggressive and social females. However, orphaned hatchlings raised by foster parents of another species can develop surprisingly even tempers and mellow dispositions, proving that their defining unpleasant nature is, in fact, a learned behavior.

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.

Z'ha'dum is the most easily angered dragon in Nadat's cave. None of the other dragons are quite sure what will set him off or why, but they know not to bother him too much. Maybe he just wants to be left alone; a few of the other dragons have been known to nag every now and then. Or maybe he really just acts up because he wants attention. Whatever the case, he's not explaining himself, and visitors are warned to be careful of him. As the saying goes, "If you anger Z'ha'dum, you will die."