Each Fever Wyvern carries a unique and very deadly disease on the spines of its tail. To make up for a lack of physical strength, the dragons use this disease to their advantage by poisoning prey and fending off attackers. The illness will quickly render victims helpless before eventually killing them. A Fever will track its prey until the target can no longer move. Usually a solitary breed, these dragons will only come together during mating season, and will flare out the brightly colored sails along their wings to help attract potential mates. Although it has been observed that the wyverns are nocturnal, they will often pick an open spot of sunshine to curl up in and sleep as the day passes by.

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.

Though his temperament was docile, and he was never particularly fond of spending more time using his venom than he absolutely needed to, Kill All Humans was pegged from the start as a vicious, unpredictable beast to be avoided at all costs. This stereotype came mostly from the humans stupid enough to try stealing eggs--also, apparently, stupid enough to not be able to distinguish a provoked attack versus randomly lashing out. After trying for years to explain that, no, he didn't hate all humans, he just didn't want anyone taking his offspring, Kill All Humans eventually gave up and embraced the reputation that had been given him.