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.

Suminoe Ako was called Ako when she was little. Because there were no other hatchlings around when she was born besides Riko, they spent their youth only with each other. That is the reason behind them sharing the same surname.

Suminoe Ako, when fully grown, became the special flight teacher on "how to sleep while flying", for the dragons that belonged to races that didn't have that natural power (for example, vine dragons, rock dragons, albino dragons, water dragons).

It was during that time that she met the albino dragon Navel Shuffle Rin, and eventually they became mates.