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.

Aionios Asteri is often considered to be one of the more reserved of his scroll, even taken in his breed's natural proclivity for quietness. Many of his brethren postulate that he is so wrapped up in his stargazing that he is often completely unaware that anyone around him is in fact speaking, and thus he isn't aware that he needs to contribute to the conversation. This theory is supported by the fact that it takes far longer to catch his attention than the attention of the other nebula dragons of the scroll. The patterns on Aionios's skin are that of a nebula unknown to humans.