Thunder Dragons are the masters of electricity. Their wings gather energy as they soar through the clouds, and when they clap their wings together they can create devastating arcs of lightning. They can stay airborne nearly indefinitely, landing only to sleep and breed; they catch their prey from the air and take moisture from the clouds. A thunder dragon’s roar is considered to be an omen of misfortune.

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.

Tesla's Muse circles endlessly in the sky above the Breedery mountain's rocky, uppermost spire. Most of her fellow Thunders prefer to range wider, covering huge swaths of sky, but Muse feels possessive of the Breedery. She is aware of her wild origins, but her memories begin with hatching in the warm safety of the Breedery's creche, under the watchful eyes of the Breedery-Master. She is one of many who were brought up largely by Schyller the Copper, and she remains fond of him. But it's Lurhstaap she looks up to. Muse has no interest in the harsh struggles of wilderness life and thanks the Guardians daily for her luck. Here she never goes hungry or worries about humans, and has endless options for male attention. Yes, life is good for Muse at the Breedery, and she intends to see that it stays that way. So she circles, tasting the clouds, watching for any sign of trouble. Between Muse and the Black called Summit-Shadow, nothing can approach by land or air without being spotted.