The foundation of Crisis on Infinite Earths developed through a character called the Monitor, introduced in Wolfman's The New Teen Titans in July 1982 before the series itself started.

Eventually, both the heroes and villains are 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.

[5] The concept of the DCU has provided DC's writers some challenges in maintaining continuity, due to conflicting events within different comics that need to reflect the shared nature of the universe.

[10] Wolfman began to attribute this to the DC Multiverse, feeling "The Flash of Two Worlds" had created a "nightmare":[2] it was not reader-friendly for new readers to be able to keep track of[14] and writers struggled with the continuity errors it caused.

[2] In The New Teen Titans #21 (July 1982), Wolfman introduced a new character: the shadowy, potentially villainous Monitor; this laid the foundation for Crisis on Infinite Earths.

[16] Soon afterward,[17] Wolfman pitched Crisis on Infinite Earths as The History of the DC Universe,[16] seeing it as a way to simplify the DCU and attract new readers.

[2] Pérez says he was not the intended artist for Crisis on Infinite Earths,[24] but was excited when he learned about it, seeing it as an opportunity for "revenge" against Marvel, which he blamed for blocking the JLA/Avengers crossover he had been working on.

[21] The idea for Crisis on Infinite Earths was first noted in the December 1981 issue of The Comics Journal, which mentioned a twelve-part maxiseries scheduled for 1982.

[8] The close spacing of Crisis on Infinite Earths and Marvel's similar crossover Secret Wars caused some fans to create conspiracy theories about idea theft.

"[28] Elements to set up Crisis on Infinite Earths were put in DC's comics years before the crossover took place;[29] an example of this was the Monitor's appearance in The New Teen Titans.

[30] The following comic book issues were labeled as part of the crossover; their covers contained a banner that read "Special Crisis Cross-Over", along with the logo for DC's fiftieth anniversary.

The conflicting stories of the DCU are explained as a Multiverse, containing many parallel universes and alternate versions of the characters, with the primary DC continuity referred to as Earth-One.

To combat this, the Monitor recruits heroes and villains from across time and space to set up five towers, to help merge the multiverse back into one to make it stronger.

[34] However, the Monitor knew this would happen and his death releases enough energy to project two of the last five parallel Earths into a protective limbo that nullifies the wave.

[35] The Anti-Monitor recruits Psycho-Pirate to his cause, infusing him with part of his power to manipulate the heroes of Earth-4, Earth-S and Earth-X against the rest; this fails when all five Earths enter the limbo universe.

The Anti-Monitor waits for Alexander Luthor Jr. to reopen the portal between the positive and antimatter universes, capturing the heroes, but a magically empowered Spectre creates an energy overload which shatters space and time.

[41] A cosmically empowered Anti-Monitor attacks again, transporting the new Earth to the antimatter universe and summoning a horde of shadow demons who kill Dove, Lori Lemaris, Green Arrow of Earth-Two, Prince Ra-Man, Clayface, Bug-Eyed Bandit, Kole, Huntress, Robin, Sunburst, and Ten-Eyed Man.

[29] Fellow IGN writer Jesse Schedeen named Crisis on Infinite Earths one of the best DC crossovers, agreeing it was unprecedented and dramatic.

[11] A novelization of Crisis on Infinite Earths was written by Wolfman and published by iBooks in 2005, with cover art by Pérez and Alex Ross.

[citation needed] Though it was not the first large-scale comic book crossover,[b] Crisis on Infinite Earths is generally credited with popularizing the idea.

The writers of Convergence all had fun writing stories set during Crisis on Infinite Earths, calling the series an exciting time for DC.

[10] In addition, Wally West replaced Barry Allen as the Flash, the Justice League's roster was changed, and characters DC acquired from other companies, such as Fawcett Publications and Charlton Comics, were integrated into the DCU.

[22][55] The practice of re-envisioning characters in the new DCU lasted well into 1989, with properties such as Green Lantern, Hawkman, Black Orchid, and the Suicide Squad all being rebooted.

[57] Crisis on Infinite Earths has been referenced several times in the various television series that comprise the Arrowverse, starting with the first episode of The Flash which aired in October 2014.

"[58] The storyline inspired the 2019 Arrowverse crossover, also titled "Crisis on Infinite Earths",[59] with the original date seen in the pilot episode of The Flash having been moved up by five years as a side effect of time travel.

[62] The story serves as inspiration for "Crisis on Infinite Earths", an Arrowverse crossover event consisting of an episode each of Arrow, The Flash, Supergirl, Legends of Tomorrow and Batwoman.

[8] The second part of the trilogy, the seven-part Infinite Crisis, was written by Geoff Johns and illustrated by Phil Jimenez, Pérez, Ivan Reis, and Jerry Ordway.

[67] In Final Crisis, Darkseid arrives on Earth and begins a conquest to overthrow reality, as part of a plan by Libra to conquer the Multiverse.