of having to give up his entire adult lifestyle. As the series progresses, the appearance of supernatural beings and situations lead Jack to become entangled in a larger, universal fight. While he protests his involvement, he is dragged deeper with each novel into growing unrest and chaos—the observable effects of a cosmic battle for all existence. The two major forces involved are called (by their earthly agents) the Ally and the Otherness. The Ally "collects" worlds as souvenirs, the Otherness "consumes" worlds as a predator. The conflict is thus not so much a matter of "good and evil" as "indifferent and inimical". It is stressed repeatedly in the novels that though both forces require control over all of existence, the value of individual worlds is negligible—but it is also stated that Earth is of greater-than-average value as it is a world containing sentient life. Sentience is rare, making this world more attractive to the Ally—much like a stone with a distinct shape or pattern. The Otherness (and its agents) derive sustenance from destruction and thus finds sentient life useful as it can be guided to destroy its surroundings and itself—like self-slaughtering cattle. This is the reason the indifferent force has been dubbed the Ally—but this definition extends to humans only so long as they serve its ends. The Otherness has a powerful champion dubbed the Adversary—an evil magician once known as Rasalom. Ages past, Rasalom made a deal with the Otherness; in exchange for power and eternal life, he would lead the Otherness's minions—malevolent supernatural entities—in its campaign against the Ally. Jack has met him several times, each time barely surviving the experience. The Ally once had a corresponding champion dubbed the Sentinel—a warrior known as Glaeken. Soon after Rasalom was empowered, Glaeken was given a magical sword that strengthened and healed him while weakening and harming agents of the Otherness. Thus empowered, he was directed to lead the Yeniçeri—orphaned children raised to fight in the Ally's cause—against Rasalom. At some point more than 1000 years ago, Glaeken became estranged from the Yeniçeri and left them to their own devices. The battles between the Adversary and the Sentinel continued—to the point of Glaeken temporarily slaying Rasalom multiple times—finally, Glaeken succeeded in overpowering him approximately a thousand years ago. However, Glaeken had grown to enjoy his agelessness, and knew that it would end with Rasalom's death. He thus sealed him in