After Inifinte Crisis, the existence of a new Multiverse, which has similarities to the original DC Multiverse has been revealed. A significant difference between this Multiverse and the original is that this one has exactly fifty-two Earths, labeled as New Earth and Earths 1 through 51. The fifty-two Earths were at first, identical to New Earth with the same history and people until Mister Mind devoured portions of each Earth's history, which altered their timelimes and resulted in new, distinct Earths with individual histories. The new alternate realities aren't duplicates of the realities that came before, and feature characters who didn't exist in the original Multiverse and are native to that Earth. For example, a version of Green Lantern exists on Earth-5 and a Nazi-themed version of the Justice League exists on Earth-10. Each of the fifty-two Earths have their own parallel dimensions, divergent timelines, microverses, etc. For example, the Wildstorm Universe has long been established as being connected to its own infinite number of alternate worlds, and concepts such as time travel, reality warping and Hypertime have traditionally served as means to present alternate timelines in mainstream comics.
The Guardians of the Universe serve as protectors of the new Multiverse. Each universe within the Multiverse is separated by the Source Wall, behind which Anti-Life keeps the universes apart. The Bleed permeates the Anti-Life in unpredictable places behind the Source Wall, allowing for transport between the universes. Due to its unique position, the destruction of New Earth would set off a chain reaction that would destroy the other fifty-one alternate realities at the same time, leaving only the Antimatter Universe in existence. As a consequence of Alexander Luthor's attempts to recreate the Multiverse, fifty-two new Monitors were created to oversee the 52 realities created afterwards. The Monitors seek to protect the Multiverse from people who crossover from one alternate reality to another, through the Bleed or through innate ability, who the Monitors have labeled "anomalies".