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.

His cave is near the cave where the great Sura lives. Though he's one of the youngest in the cave, Terciel is a great leader. He doesn't fly and rarely hunts with others, but they consider him smart and pretty strong and no one knows that he is not strong. His stone scales are mostly surprisingly soft. Even a hatchling could hurt him. It's because he had a terrible softshell disease as little egg. He hates wars and never fights, mostly because he is afraid of possibility that someone from his cave would get hurt. He is also one of the few that wanted answers to their questions from Sura, got them and returned back. He sometimes sneaks out of the cave, goes somewhere and appears next morning full of joy. Nobody knows where he goes, though lot of dragons tried to follow him and figure it out.