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.

This dragon was named "Bonesaw" for her collection of tools. Not content with her natural skeletal armor, she scavenges bones from her victims and shapes them with her tools and magic in order to add them to her bone plating. Bonesaw has built up quite an impressive collection of armor, taken from corpses of all kinds. She is mentioned in Wildbow's story, Wyrm, though her character has been altered somewhat.

In the story, Bonesaw's experimentation with armor is taken to a whole new level. The fictional Bonesaw takes not only bones but also other essential parts from the corpses, and tries to add them to herself or her victims to create strange new lifeforms. The dragon in the story considers herself the biological expert of the Nine, and is feared by many. Ironically, the fictional Bonesaw is just on the verge of maturity, and is even considered cute by those unfamiliar with her darker side.