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.

Cathal is currently the only female Shadow Walker under the command of Nemesis. She is mischievous and is always right on Marrok's heels when trouble arises in the cave or they need to do their daily mischief. She is like his wingman, always there beside him. If Marrok says something, Cathal backs it up as best she can. The two don't get along all the time, however. Cathal is known to be rather clingy, and often sticks to Marrok's rear as they are pulling off tricks. He snaps insults back at her, but she's too slow to understand them.

For a Shadow Walker, Cathal is quite stupid. One could throw a biting insult in her face and she wouldn't understand what it means. But she's loyal nonetheless to Nemesis and Marrok. Marrok often describes her as annoying because of her tendency to 'stick' to whoever she believes is in charge.

Cathal enjoys slipping between the planes of reality, especially after she and Marrok have played a huge trick on someone. Her giggles echo from the shadows.