Cage/Spoilers

Cage, is the secondary main antagonist of Shady along with Sam Hill and Slim Shady. He is an enemy of Marshall and has the goal of taking Shady's powers for himself, through a fight with Eminem. He himself is seen possessed by a demon himself, named Sam Hill.

Behind the Scenes
Throughout the later chapters of Shady, Cage is revealed to behind Marshall's confronting and battle with Shady. Kidnapping Hailie and using a set up to have his wife almost killed, he subliminally leads Marshall to find Shady's true intentions and later himself.

Meeting Eminem
After meeting, Cage tries to convince Eminem that one of them can wield the powers of the other, having double the demonic powers. Marshall shares his belief that neither of them can hold that much power, practically going insane himself with holding the power of Shady.