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.

In the half light of darkness accented by a volcano's fiery flare, the hulking form of a Brimstone dragon lay on a heap of stones, growling rumbling snores that seemed to shake the ground. Three little heads poked up from their hiding spot, devilsh grins on their faces. The biggest hatching flicked its tail and the trio of troublemakers slunk slowly towards their slumbering target. With a barely suppressed giggle, the leader grabbed a clawful of rancid-smelling dust and shoved it into the Brimstone's nose. His snores stopped abruptly as he took a breath and sneezed loudly, spraying a small cloud of noxious gas over the hatchings. The trio yelped and scattered, unable to hide their smirks. Gronkel roared after them about disturbing his nap and rose to pursue them, but they were already out of sight. He grumbled and lay down again, but privately he was smiling. Hatchlings would be hatchlings after all. He flicked his tongue and closed his eyes, plotting a way to prank them in return.