Black Marrows are named for their dark colored hides which are encased in a distinct exoskeleton. Their skull and the top edges of their spine push out from under the skin as they age. As such, their young need excessive amounts of calcium for this armor to develop. The older a Black Marrow dragon is, the more skeletal their appearance. They often use their skeletal looks to lure in foolish scavengers or terrify predators. These vicious dragons love nothing more than to crack open bones with their stony beaks and eat the marrow inside. Voracious scavengers, Black Marrows will swarm and devour corpses both old and fresh, sometimes even dragging larger finds to the water to allow them to “ripen.” Despite their dreadful demeanour and often horrid stench, Black Marrows are devoted mates and parents.

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.

What little she doesn't eat from her scavenges and kills, this Black Marrow dragoness buries and mixes into the soil, providing fertilizer of sorts for her garden of strange, often spooky and grotesque plants. Most of them are fairly tame, but attempts by some of the Earth- and Life-aligned dragons to study them have been repelled by some of her more vicious specimens. Bloodflower is the only one who can walk among "her preciouses" unharmed, and few dragons save for the other Halloween breeds are inclined to visit her there. On moonless nights in particular, odd noises can be heard coming from the vicinity of her plot, loudest among them a deep booming voice calling out "Feed me, Seymore!"