Originating from a single species that thrived in ancient times, Xenowyrms have become an incredibly diverse breed whose appearances vary depending on their habitats. Each Xenowyrm subspecies is heavily reliant on the power of different types of mana, making them powerful magic users. Astrapi are easily the most temperamental of all Xenowyrm subspecies. Their unpredictable behavior—coupled with their masterful control of lightning magic—has the potential for devastating results. Most of their time is spent airborne, flying through the skies or circling mountainsides for prey.

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.

Despite being an Astrapi dragoness Heather has a rather even temperament—well most of the time. She can become quite volatile if she or her mate are provoked or threatened but in the meantime she is a calming influence on him as he is on her. Heather is more than happy to live a quiet life away from other dragons. She is content with just her mate to keep her company. So her worst phases of temperamental anger usually happen when MacLeod is away on some heroic quest. Other dragons have learned long ago to avoid her in those times as the results of meeting her can get quite nasty; so nasty in fact that she doesn't even tell MacLeod about what happened while he was away. She wouldn't want him to stay around all the time just for her sake when there's dragons to save elsewhere after all.