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.

Kuroi or Ku-chan is the strongest guardian for the group's territory despite not having strong shield like Kokoro or hard shell like Houseki but she makes up with her ferociousness and he heavy tail and wings which are covered in razor-sharp stones which will turn whoever dare to try to sneak into the group's territory into shreds. In contrast though, she is very gentle toward the other group members.