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.

If one asked any dragon in the cave to name every dragon they knew, one could bet almost anything that Zorak would not be on that list. Few outside of the Libra Clan even know of his existence, and even its members could easily forget about the silent black marrow. Zorak spends most of his time alone, locked in the study of books, and can easily forget about such basic things as eating or sleeping. Silence is Zorak's friend, and he revels in being alone with his thoughts and inky marks on a sheet of paper. Occasionally, an exploring hatchling or a safety inspector will come along the passages in which Zorak lies, and after several instances Zorak now carries around a sheet of paper signed by Regan, the clan leader, stating that he is a member of the clans and not a wild dragon intruder. Regan is one of the few who knows of his presence there, and while she sometimes worries about him, she is content to leave him be in the peace that he desires.