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.

Zooplankton swims in the open ocean and the bay called the Sterling Sea, doing little more than what's needed to survive: eat, sleep, escape or fight assailants, check his mana supply. A solitary dragon, he has no connections with anyone, but he also has no enemies. He wonders if he should find a hobby or mate sometime, but he doesn't think he'll be very good at keeping either. The last thing Zooplankton's caretaker said to him before he left home and headed northeast for the Sterling Sea was "Oops-a-doops". What that means, if anything, will remain a mystery for him, and his mind wanders to that remark whenever he's suspended in the water and looks southwest.