Terrae Dragons are primarily herbivores who prefer to eat from the tops of trees. However, due to their massive size, they must rely on small, specialized scales to absorb and convert energy from the sun. Since they live in tightly-knit groups, this form of energy absorption helps preserve the forests in which these dragons reside.

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.

One of the clan's nine oldest dragons, known as the elders, Rheja has always been an important member of the Thoiris clan. When the clan was just being formed, she was always the one to cheer others up when everything didn't go well, and her constant optimism prevented the elders from giving up many times. Even when big problems come, she stays calm and does her best to help out. Her mate is Crain the hellfire dragon, and though they disagree on many things, they have always stayed side by side.