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.

When Sanada hatched he already was rebellious and reckless. He attacked hatchlings which came near him and he snapped another adults when they tried to force him participate into teamwork, such as hunting for the hatchlings. He is quite a lone wolf and does not care about other creatures, not even about his owner. Though he does not attack without a reason, but he is a feisty dragon, so one should better not mess with him. However Sanada suddenly changed when Yukimura, a female Hellfire Dragon hatched and it seems he is in love with her.