Shadow Walkers are a strange breed that possess the ability to slip between the planes of reality, becoming immaterial. This allows them to hide in the shadows, either hunting from the concealment of near invisibility or evading enemies. Though they become corporeal to mate or to eat, they spend most of the rest of their lives walking in the shadows. Shadow Walkers are wary creatures, though on dark autumn evenings when the leaves fall to swirl in the chill, rain damp air, they may be seen drifting out from the shadows.

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.

Iormungr Bjartskular was an enigma. After dying in the Fall of the Riders, all beings forgot much of who he was. Not even his scales' color or rider's name are known. The only information retained about this mysterious dragon is that he was the mate of Vervada, a wild dragon who laid many an egg, but donated only one to the Riders. This egg hatched into Saphira, who slew the dark king Galbatorix with the aid of her rider, Eragon, and many Eldunari.  Iormungr's physical remains were destroyed completely; both his skeleton and Heart of Hearts were vaporized during the Fall; but his spirit is said to live on earth, walking among the colorless Shadow Walkers, drifting through bleak shadows, searching for the mate who he will never see again.