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.

Rathalos patrols his territory on fiery wings. He is the self proclaimed "Ruler of the skies". Like most other Hellfire Wyverns, he has a particularly foul temper, and is extremely territorial. He is very aggressive towards any dragon, of any breed and gender who enters his territory, and fearlessly does everything within his power to drive them off or kill them. Though, he finds the latter much easier. He's been known to take on dragons twice his size, or dragons half his size, and fight tenaciously, until he has won. Though, victory is not always the case. Rathalos has but one fear, which is his mother, Reylene Jemmyns. If you think he's bad, think of where he learned his behavior from, and know that Reylene is twice as savage.