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.

When Phaos was a hatchling she saved her parents from a dragon slayer's attack, but when she tried to flee from the dragon slayer he pierced her heart with his sword, mortally wounding her. Since both of Phaos's parents had escaped him, the dragon slayer left the area, abandoning Phaos's corpse to rot because there was no profit in taking it with him. Hours later, a wizard happened across Phaos's corpse and tried to revive her, only to panic and flee when Phaos rose as a half Black Marrow, half Zombie abomination. Phaos, not understanding what had happened, tried to go home to her parents, but they and a mob of other dragons drove her away. Phaos fled, and only after catching sight of her reflection in a puddle did she realize what had happened. Ashamed of what she had become, Phaos hid herself away in a crevice on the side of a cliff, hoping that no one would ever find her. Weeks later her parents came looking for her, but Phaos stayed hidden, too afraid to face her own family.