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. Gaia, despite their large size, are the lightest of all Xenowyrm subspecies. They possess the ability to use incredibly powerful life magic, though most of their efforts are concentrated; to them, nothing is more important than letting plant life thrive. Adult Gaia will use their magic to grow vegetation around themselves so they can spread it wherever they travel.

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.

Kastano is the leader of all Gaia Xenowyrms that share his territory. He makes sure they fulfill their duties and don't abuse their powers, and he enforces the rule about never interfering with the lives of mortals with a rabid intensity. No one is sure why he's so strict about it, but they suspect it has something to do with the section of jungle that he's walled off with brambles. No one is allowed to enter save for himself and a trusted few. Some of his younger subordinates like to joke that it's where he keeps his sense of humor.

Despite his cold, emotionless exterior and intense work ethics, Kastano is well liked by the other dragons and wyrms in his lands. For some reason they're filled with a determination to please their boss and protector, and making the grumpy old Gaia smile has become a badge of honor among them. Kastano deeply appreciates their efforts, though he'll never admit it.