When Water Dragons mature, they lose the ability to survive on land, entering the water permanently. They are adept swimmers and eat whatever fish are in the lake they live in. They tend to inhabit the same lake for their entire lives, although a few live in the ocean and swim all over the world.

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.

Nienna does not live with the other dragons of the star clan. Until she was mature, she lived in the cave with the others. However, upon maturation, she was forced to move to a lake that is not too far from the cave. She appears to enjoy the visits of Luthien and the hatchlings; her demeanor changing quite dramatically from subdued to excited. This suggests that she might be lonely the rest of time. Some of the other dragons visit her as well, Gelmir most notably (accompanied by Arwen more often than not), and this also improves her mood.