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.

Isilmien Cosmos adores the moon, even more so than the stars, which is incredibly odd for a Nebula Dragon. Born in a clan of moon-worshiper dragons of many different breeds, she is a devout follower of their beliefs, even after leaving the clan. Every night, she painstakingly picks special flowers and herbs from the nearby meadows, then brings them to her cave to dry. When the moon is full, she lays out these plants in order for them to "lace their veins with moonlight". She uses these moon-plants for various purposes: she decorates her cave with them, sprinkles them on her food, and burns them. Because she is so busy with her moon-plants, she rarely has time to hunt. She has to resort to trading her moon-plants with other clan members in exchange for food.