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.

Though Stone-gaku looks like a menacing behemoth of a dragon, he's really about as violent as the stones he dines on. He naps a good deal, and enjoys basking in sunlight on cold days. He gets on quite well with his cave-mate Shozome, and the pair is often seen outside, merely sitting in silence together. <br/>On another note entirely, Stone-gaku's favorite snack is hematite, which likely accounts for his enormous weight and the faint metallic sheen to his stony hide.