Dorsal Dragons are so named because they have large fins along their backs that can be raised and lowered at will. They use these fins to regulate body temperature; they raise them to cool off when they become overheated. The bright colors on the fins double as a means of attracting mates.

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.

No dragon is as unquestionably dependable as Rathmus. He holds Zantorian's complete trust, which is almost exclusively reserved for the split leader's mate, alone. Even the black dragon Mezanec, Zantorian's eternal rival and friend, grudgingly agreed that Rathmus deserved his status as second-in-command. Though much younger than the two males, Rathmus has proven his maturity and competence in battle and decision-making. This red dorsal male is extremely thorough, responsible, and has a serious personality. He will never bend the rules for anyone, not even for himself, and fully expects others to do the same.