Stone Dragons have a tough outer covering made of a stone-like material. They eat rocks, using the minerals they contain for nourishment and to keep up their stone outer shell. They rarely move, and are the heaviest of all types of dragons. Although they have wings, indicating flight ability, no one has ever seen a stone dragon flying.

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.

Mercury seems almost like the planet he was named for, desolate and lifeless. His personality is somewhat a mystery being that he is a Stone Dragon; he rarely moves let alone interacts with other dragons. The only times he is ever seen moving is when it begins to rain; then he is suddenly found in the cave with the other dragons and they have no idea how he got in so fast. Apparently Mercury hates getting wet.