Bright-Breasted Wyverns are a breed of dragon easily recognized by their bright red markings. They are a small breed, only the size of a full-grown man. However, they have developed poisonous barbs on their feet to make up for their size. Their coloration is used to warn off potential predators of the danger, and is also used to attract mates. They are very social, and can often be seen preening in large groups.

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.

Nsisr is the dental hygienist in Crater Moon's office, cleaning up the mouths of patients and taking preliminary notes on their oral health for later reference. She uses her poison to create a special toothpaste to treat mouth infections and gum disease. Because she only generates so much poison, the supply of this paste is limited, but she does have a baking powder toothpaste she makes and distributes to all patients. She is known to lecture about the importance of good nutrition in maintaining good oral health. Sweetlings may do fine with tons of sugar, terrae really shouldn't be eating meat, and bleeding moons should limit their pasta intake (as she keeps telling Haizou), but magically-synthesised food-like products are unhealthy no matter what diet an individual is adapted for. For those who are afraid of the dentist, her lectures make a trip scarier, but by following her advice they may need to come in less often.