Daydream Dragons are the hosts of daydreams and fantasies. They spend the majority of their time sitting on clouds, dropping daydreams down into the minds of people passing by. Humans who live near Daydream Dragons must be especially careful not to let their thoughts wander, or they could end up spending hours or even days in a trance-like waking dream state.

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.

Celestiria is one of the main pranksters of Sierra's pack. Her ability to drop daydreams on people has given her a lot of ideas. Her main way of working is to sit in a tree with extremely dense foliage so no one can see her vivid colors and thus be able to drop daydreams on them easily. Luckily, Sierra knows how to tell if someone got affected by Celestiria and is mostly able to undo her work. Celestiria knows that she gets in trouble for doing this, but she still does it. She shares a particularly good bond with Viridiase and Tundraesa and those three dragons are always found together no matter what.