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.

Core is not his real name; his real name is unknown, for he disposed of it when he joined the Clan of Darkness. Utterly brainwashed by Khymal, he is intensely devoted to serving the clan: he cares to his clan-kin tenderly, and is fiercely xenophobic of others. Greatly suspicious of those not of his kind, he has more than once discussed with the others about making the clan Black Marrow exclusive, though Khymal still preaches to other breeds.

Like all others in the clan, he was given his name only after being with the clan for some time and showing his true self and personality. Dubbed "Core" because of his devotion and how he had become such a large part of the small group, he in fact wishes to make himself a larger part of the group—he wants to have children. His greatest obstacle has been his xenophobia, as he has been barren with others of his kind, necessitating a mate of another breed. Whether his fear and hatred or his love and kindness will prevail is as of yet unknown.