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.

Fwi has a sign at her cave's entranceway that says, "Fiery Hot Deal! Inquire within!", which she picked up in her youth. It was posted at the edge of a town she had just begun terrorizing. She stopped to study it—she had no idea how to read and was growing irritated that the apes could foil her intellect with some sort of code. The humans soon ventured over and were treated to the sight of a wyvern hunched in front of their fence like a jagged-winged hen. Fortunately for Fwi, they were very forgiving and didn't try to kill her, and fortunately for the humans, Fwi lost her desire to stomp around and set things aflame. The landlord let her take the sign and gave her a basic language scroll that his children had outgrown, and she happily lumbered away with the presents under her wings. She sometimes smacks her husband with the sign when he expresses the impossible-to-achieve desire to fly to outer space.