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.

Despite having been raised by the AnselaJonla flock, Yvonne sometimes behaves more like a wild Hellfire Wyvern. She is usually found in the company of a flock of wild ones that occupy a dormant volcanic crater, where she battles for dominance of the pack. She's a good fighter, and often ends up as the pack Alpha for a time.

Yvonne likes to compare her species to the small carnivorous mammals known as spotted hyenas. Like Hellfire Wyverns, their packs are ruled by the females of the species, with no male ranking above a female. The females care for the young, and the males are lucky if they're allowed near.

Yvonne's favourite mate is not, to the surprise of most, another Hellfire Wyvern. No matter how many wild mates she takes, she always returns to the flock and Arthur, a Radiant Angel.