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.

In the dark night of October the 31st 2010, when GiratinaOF and his two Sweetlings were searching for treats, they found four similar eggs outside, near a cold, rocky wall. GiratinaOF brought them inside so the other dragons could take care of them. When these 4 eggs hatched, many little dragons were frightened of the scary hatchlings. This didn't change when these hatchlings grew to adulthood. The males were named "Black-Marrow" and "Sable-Marrow", the females were "Sable Marrow" and "Dark Marrow".

Dark Marrow is the girl of Black-Marrow, the strongest Marrow dragon in the cave. She's more lazy and inactive than the others and gets very angry if it is too loud or wakes her up while taking a break. Still, she's very popular as a friend and called wise and lucky among the adult dragons. When Dark Marrow isn't sleeping, she's hunting or just flying through the night. She is often hunting in the water, where not many dragons go for hunting, and eats fish or animals coming there to drink.