Black Dragons are warriors. They are strong and capable in battles of force, but also ample magic users, capable of devastating opponents with their spells. Their bright eyes give them excellent night vision, which is why they generally hunt during the night.

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.

A member of the Sylvain clan's search-and-rescue team, Oyumi is the lead lookout during recovery missions. With the best eyesight on the team, she is able to discern the injured target and predators from miles away, even during low visibility conditions. While the rest of the currently active team works, she watches from the skies, alerting them of potential threats or obstacles and guiding them safely back to the caves. Her mission partner and mate is Otsuchi, whom she tirelessly looks out for and fusses over, to the rest of the team's amusement.