Brimstone Dragons live in dry arid areas such as deserts where they feed mainly on sheep, goats and the occasional camel. Their favorite habitat is ideally situated close to the wastelands around active volcanoes. This is due to an important part of their diet—sulfur, which they obtain from deposits near volcanic gas vents. Instead of fire, these dragons use the sulfur they ingest to create a noxious gas which they store in their large throat pouches. When in danger, this gas is released in a large cloud. They also eat other mineral rich substances—including charcoal—and will drink the mineral rich (but slightly acidic) water commonly found in deserts and volcanic regions.

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.

Brimmis desires riches above all else! He collects shiny golden treasures that appear to be the golden color of the desert sands. Brimmis lives in Clya's Cave and protects his hoard almost savagely. He ignores the other dragons in Clya's cave, and has no desire to find a mate. He has scales the sickly yellow of exotic poisons. His scales are strong after years of protecting his hoard before finding the cave, and therefore have created a strong, protective armor.