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 a different type of mana, making them powerful magic users. Thalassas are a unique variety of Xenowyrm in that they are the only subspecies known to dwell in marine environments. Their porous skin and slender build are perfectly suited for the aquatic terrain, but they can only survive for short periods of time on land. Powerful users of water magic, they can create large waves and alter currents with a simple thought.

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.

Xymr is Xenokiri's mate. She regrets the day she met Xenokiri—he tricked her into being with him, passing himself off as nothing short of a kind soul. But when she discovered his true nature, it was too late. Fear of him controls her actions—she nods along to everything he says, even if she doesn't agree; she is afraid to leave the cave without his permission; she is terrified that one day she'll say something that upsets him. Her entire life is under control of someone she dislikes, and she is ashamed that she does not have the strength to stand up to him. She plans to start an uprising, but does not know how to contact the elder dragons of the original clan without arousing suspicion. Her magic isn't strong enough to defeat Xenokiri alone, and she knows this. In fact, she doubts that the strength of every other dragon in the two clans combined is enough. She knows his true power, so, instead of directly attacking him, she quells his anger enough to avoid large-scale destruction.