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.

Nijiiro Yume has dreams of the human world, and what goes on within. She seeks to ease the pain and weariness in people's hearts by allowing them to loose themselves in a dream. She gives humans inspiration, hopes, and wishes, and gives them the strength to make their dreams come true. She wonders why humans are so tied to reality, when in dreams, anything can happen. She hopes that humans will one day help one another to make each others dreams come true instead of fighting and ruining wishes and hopes.