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.

Nexus is a flighty, easily-startled female with a strange dislike for water. This may be because, when she was but a hatchling, she fell in the ocean and almost drowned, but was saved by Zant. The Nebula, since then, has absolutely refused to have anything do do with water besides drinking it.

Family obviously has a strong effect on Nexus; she shares her mother's love for lemons, and often chants something about burning houses down to the ground with them. She also has the oddest fascination with taking part in GLaDOS's testing facility, the Aperture Canyons--she even went so far as to work for the crazy dragon.

Nexus, during her time in the facility, will help test subjects by holding down buttons or helping them with counterweight systems. She will not tell them how to escape, nor will she guide them, but she is useful for simple things--mainly weight, another helpful presence, and conversations about lemons.