At the start of "Crisis on Infinite Earths", the Anti-Monitor (the Monitor's evil counterpart) is unleashed on the DC Multiverse and begins to destroy the various Earths that it comprises. The Monitor tries to recruit heroes from around the Multiverse but is murdered, while Brainiac collaborates with the villains to conquer the remaining Earths. However, both the heroes and villains are eventually united by the Spectre; the series concludes with Kal-L, Superboy-Prime and Alexander Luthor Jr. defeating the Anti-Monitor and the creation of a single Earth in place of the Multiverse. "Crisis on Infinite Earths" is noted for its high death count; hundreds of characters died, including DC icons Kara Zor-El (the original Supergirl) and Barry Allen (the Flash of the Silver Age). The story's events resulted in the entire DCU being rebooted, dividing the fictional universe's timeline into "pre-Crisis" and "post-Crisis" eras.