Mint colored dragons are the most peaceful of all dragons; they only eat plants unless they scavenge meat from an already dead animal. They also have no ways to attack others or defend themselves. They are much smaller than other forms of dragons since they only double in size when they mature. Mint dragons are unable to use magic and cannot fly since they lack wings. Their looks have given rise to the common insult of calling dragons “large lizards.”

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.

An incredibly shy dragon, Yume loves nothing more than to lurk around the CPA's castle. Even though she would also like to interact with the members of the group, she tends to just stay on the sidelines and watch. Because of this her main, and possibly only, friend is the Phantom that also haunts the place.

Whenever someone does speak to her, she tends to become very nervous and has a rather quiet voice when telepathically communicating with anyone.

Outside the CPA castle grounds, Yume is rarely seen or heard from by most of the residents of the cave. Those that have seen her claim that she's often helping out with the musicians or other performing dragons plan their current routes and tourings. Others claim she tends to some of Andy's many adopted hatchlings, or that she's gearing up to meet with her friend at the castle once again.