Geode Dragons are closely related to Stone dragons. They are covered in a hard stone-like material as well as beautiful crystal. Their wings are entirely useless for flight, but they help attract mates. The dragons with the most brilliant and colorful crystals are more likely to mate.

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.

Named after the Latin word for "strength", Nerva has also received the epithet "Ryuueisei", which is Japanese and means "Dragon Crystal Star".

Different from the other dragons of his kinds, he does not care about his appearance. In the contrast, the sparkling of his crystals annoys him, because they make it difficult for him to hide and to launch a surprise attack. He only desires for strength and victory. Due to his masculine behaviour, he still attracts the females.