Seasonal Dragons take on the characteristics of the season during which they are born. Thus, eggs that are laid in spring match the pink flowers and green buds of spring, and those that are laid in the summer grow to depict the bright green of the forest trees and the yellow of the sun. Eggs laid in autumn display the bright colors of leaves falling from trees, and those that are laid during winter take on the appearance of the icy snow.

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.

Kaos Zero and Biting are Autumn twins. Twins and even triplets are quite common in the dragon world, however these two are caveborn. It is unknown how or why, nor do the the males know themselves, but they've lived side by side as long as they can remember.

They can be easily mixed up, but their characters slightly differ. Kaos Zero is more daring, the one who decides on almost everything and dominates. Biting is less bold, though more fun, skilled and laid-back. Kaos often likes to be in charge, but he knows if he disrespected Biting's opinion, the twin would angrily leave and never come back.