Named after their cloudy, ashen scales, Ash Dragons are large, gentle beasts, although their faces can give unaccustomed folk a fright. Their tough scales and sheer size make them infrequent attack targets, traits that explain why pygmy dragons and other small dragon breeds can often be seen riding on their backs, hiding amongst their large spiked scales. Though they tend to be mostly quiet, Ash dragons have a low, deep roar that is typically only used to threaten or call to others of their kind.

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.

When it was discovered that the protrusions around Gristmill's tail and hind knees are the "perfect" texture to grind grain into flour, the previously-unoccupied ash soon gained five mill workers and a repairman, sitting on him and using their contraptions and bags. When they described to him the building they call a gristmill, Gristmill decided to call himself that, too, for ease of recognition. Sometimes it's a hassle to accommodate them, and Gristmill is usually immobile as they work. When passengers are particularly fussy, he wonders if it was a mistake to grant them permission to use him like this. However, they have been very good about bringing back to him baked goods and stews made from that flour. If Gristmill asks for a particular foodstuff, someone will bring it.