Nebula Dragons are nocturnal creatures. With the best eyesight to be found, they are often seen staring into space. Each dragon tends to observe a particular nebula and will eventually change their colors and patterns to match it. As the nebula changes over time, the dragon changes with it. The more intricate the design of the nebula, the better chance an individual has of attracting a mate. It is said that the markings on no two Nebula Dragons will be exactly the same.

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.

Regret is the head of the Seiun Clan, a clan of Nebula dragons. She was deeply obsessed with astrology and natural science, as are most Nebula dragons. But she took it much farther than most others would go, spending day after day studying and researching without rest. She's the smartest Nebula in the clan, but her methods and style of research leave her less powerful than the others as well, which doesn't affect her much due to her pacifistic nature.