Sunset Dragons are closely related to sunrise dragons. However, their behaviors differ greatly. Sunset Dragons generally live alone or in small packs. They are more active in the evening, hunting and performing all of their daily tasks as the sun sets.

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.

Atardezer is the son of Amanezer and the "princess" Niaga. Like his father, he is very honorable and dutiful, though he can be cold and quite aloof. He secretly considers himself some kind of nobility. Despite being young, he already is the leader of the hunters, who have to provide the increasing population of the valley with fresh meat.

His name is derived from the Spanish term "atardecer", meaning "dusk".