Bright-Breasted Wyverns are a breed of dragon easily recognized by their bright red markings. They are a small breed, only the size of a full-grown man. However, they have developed poisonous barbs on their feet to make up for their size. Their coloration is used to warn off potential predators of the danger, and is also used to attract mates. They are very social, and can often be seen preening in large groups.

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.

Having been abandoned as a hatchling, Rio often feels unwanted and outcasted, despite being re-adopted. He hates being alone and is incredibly clingy to any company he gets, which lead many of the other dragons to find him annoying. Some even end up acting aggressive to chase him off, feeding his anxiety of being left alone. He is usually more inclined to go over to a dragon that is on its own, as he seems to think that everybody else feels as lonely as him.

The other Bright-Breasted Wyverns are very fond of him, and try to encourage him to forget about the times he was rejected.