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.

Raised among the other species' hatchlings, Kriilunaus was seen only as a threat to the pre-existing Hellfire hierarchy. Young and vulnerable, she hid her true state of mind to avoid pain. Affected by the behaviour of her own species, she quickly became bitter and malevolent, revelling in the suffering of others.

Such behaviour was overlooked, marked as her species typical demeanour. Yet, her behaviour had very few similarities. Instead of showing open aggression, this dragon calculated the chance of an egg or hatchling falling ill and executed everything within her power to make it happen. Thus far, Kriilunaus has yet to cause the death of any of the Cave's young, though she has succeeded in making many ill. As she gains maturity, her sadistic nature is no longer satisfied with inducing the suffering of young dragons, instead moving to a more difficult target; elderly dragons. Protected by the strong, even a minor success in causing suffering feeds her ever growing inner sadist.