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.

Part of the team of dragons that guards the Sylvain family caves during the nighttime, Dou specializes in casting hypnotic magic, usually through eye contact. As such, his eyes are rather sensitive, and he tends to avoid light whenever he can. Apprehensive and wary of everyone around him, even family, Dou rarely speaks to others, preferring to rely on himself for sustenance and support. He practices his magic on small animals or the prey he hunts, and trains only by himself, to prevent others from discovering the extent of his techniques.