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.

Hakkar's ferocity is matched only by the heat of his flame, giving him the rank of Warrior. He will sit behind Slumber when she sleeps, and when she is awake to guard the inside of the cave, he will sit at the entrance and screen all visitors. He is especially keen to investigate the males, he has a soft spot for Belladonna. He knows she is flirtatious but does his best to impress her with his fiery displays of courage and worth.