Dark green dragons, once they mature, appear to become an entirely different species. However, this isn’t true. Rather, they burrow underground and get nutrients from their vines. These vines are sometimes referred to as Dragon Grass. These dragons are very violent, and will use their vines to capture, kill, and eat anything that moves, as well as nearby plants. Luckily, their range is limited and they cannot use magic. Dark green dragons tend to be easy to spot since they usually kill all plants around them and thus are usually surrounded by a large clearing.

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.

Koyuko-Un is a very determined Vine dragon: though he doesn't want much, he almost always gets what he wants. Most often, he wants a 'piece of the sky,' which, in human language, is a sapphire. He is obsessed with sapphires and hoards them almost as much as he hoards cacti (his favorite plant). Like many of the Vine Dragons in Kaoru's Cave, Koyuko is weird and has strange quirks: most 'normal' dragons avoid him. In truth, however, Koyuko is just artistic... in several ways. His love language is gifts, and he daily gives gifts he finds to his close friends.