- "December 10, 2019. On that day he will answer the call and make the ultimate sacrifice. Soon, this world will fight for the fate of all the known universes."
- —Mar Novu warning Barry Allen and Iris West-Allen the Crisis is near[src]
The Anti-Monitor Crisis, commonly referred simply as the Crisis and also known as the World Wide Crisis, was a massive, apocalyptic event that encompassed the cataclysmic destruction of every single Earth in the multiverse by the Anti-Monitor's wave of antimatter, leaving only the chosen Paragons as the last survivors.
Oliver Queen would later on become The Spectre, gathered the Paragons and reformed the multiverse and a new universe that is a merged Earth-1, Earth-38, and Earth-TUD5 to Earth-Prime before an alliance of heroic teams banished the Anti-Monitor to an eternity of shrinking. This also resulted into a formation of a Special Task Force in order to put down further threats to the new multiverse.
In the original timeline, the Crisis took place on the night of April 25, 2024, where both the Flash and his nemesis Reverse-Flash traveled back in time to March 18, 2000 to create the current timeline, resulting in a temporal loop that allows the Crisis to happen in every timeline regardless, except the Flashpoint timeline.
Due to a change in the timeline in which Team Flash destroyed Cicada's dagger in 2019, the Crisis occurred much earlier, from December 10, 2019 to January 2020. However, it appears that the Crisis itself has changed as well, as the fight between the Flash and Reverse-Flash in Central City did not happen in the current timeline.
Around 7980 B.C., on the planet Maltus, Mar Novu was experimenting with time-travel to witness the birth of the universe, only to accidentally end up in the anti-matter universe and reveal the multiverse's existence to his antimatter doppelgänger, Mobius. He learned that the Crisis was supposed to happen in 2024. In preparation, he built Quantum Towers on several Earths to defend against the attack. He began testing different Earths throughout the multiverse by bestowing the Book of Destiny to an individual from the Earth he was testing, and let them create their own Elseworlds.
Sometime in the 22nd century, a speedster named Eobard Thawne/Reverse-Flash began to study the life of his archenemy Barry Allen/The Flash, after he somehow discovered his true name and acquired knowledge of his parents and loved ones; Nora Allen, Henry Allen, Iris West-Allen and his daughter Nora West-Allen (in which was presumably named Dawn in his timeline). When he gained knowledge about everything from Barry's life, Eobard decided the best way to defeat Flash was to murder Barry as a child. However, before he did this, he wanted to have a last encounter with his arch-enemy.
Somehow the Anti-Monitor was freed and the Crisis began, prompting Novu to gather the heroes to help him save the multiverse. During this, Thawne, having gained help from the Anti-Monitor's shadow demons, arrived to April 25, 2024 and gained the attention of the Flash and his allies: Green Arrow, Hawkgirl, and The Atom. They started fighting on the streets of Central City causing the most destruction the city had ever seen. The fight (and possibly the antimatter) caused the sky to turn a deep crimson color.
At some point during the battle, while Green Arrow yelled in the background, The Flash recorded a message for his daughter to see in the future, knowing he had little time left.The battle caused several trucks to start leaking their contents onto the streets and caused power outages spread over 20 blocks throughout the city. The Atom left the fight and aided the Central City Police Department in evacuating all the nearby buildings during the power outage. The speedsters then started battling over two overturned tanker trucks, and the lightning emitted from them caused the oil from one of them to ignite. While surrounded by smoke both speedsters had a very heated conversation on an unknown matter, and then the two sped off leaving Green Arrow, the Atom, and Hawkgirl behind. The two then continued their fight up and down an unknown avenue before they vanished in a flash of light.
Unknown to everyone, during the explosion, the Reverse-Flash traveled back in time to March 18, 2000 to kill his nemesis as a child (like he planned before). However, the Flash followed his nemesis back through time. The two fought inside the Allen house around Nora Allen, each landing solid hits on the other, but their skills were fairly equal. Eventually, the future Flash proved to be the better of the two. When the 11-year-old Barry came into the room, Nora was in the center of it, surrounded by streaks of yellow and red lightning and caught a brief glimpse of the Reverse Flash's face.
During the fight, the Flash saw his younger self from 2015 during his first trip into the past and signaled him not to interfere, because of what would happen to the timeline if he did. As the Reverse-Flash moved in for the kill, the future Flash intervened and transported his younger self to safety 20 blocks away, much to the Reverse Flash's outrage. However, Reverse-Flash quickly theorized another way to achieve his goal: to kill Nora and frame Henry Allen for the crime in the hopes that such a tragedy would traumatize Barry enough that he would never achieve his destiny, and Eobard would be free to return to a future without the Flash, so he grabbed a kitchen knife and stabbed Nora in the heart and fled the scene to return to his own time which he hoped would now be one without the Flash.
After Flashpoint, Savitar killed Iris and continued the loop of his existence, causing Julie Greer to be hired and to replace Iris with writing the article. However, thanks to the efforts of Team Flash that caused Savitar to be erased from existence, Iris's name was once again restored as the author of the article.
According to an article from the Citizen in 2049 that Nora West-Allen presented to Barry, the Flash was still missing 25 years after the Crisis. Roger Hayden/Psycho-Pirate, said that during this crisis, entire worlds lived and died, implying that the Crisis was more than just a fight between the Reverse-Flash and the Flash.
In 2018, Novu tested the Earth-90 and like many others, it failed. After this, he traveled to Earth-1 to test it by bestowing the book to John Deegan. He was genuinely impressed when the heroes of that Earth were able to steal the Book Of Destiny, something that had never happened before. He started to respect Earth-1 even more when Oliver Queen came to confront him, in his realm, without any sign of fear, demanding him to change the destiny of Barry Allen and Kara Danvers. Impressed by the heroes of Earth-1, with Queen in particular, Novu gave him the means to save the two, but in exchange for helping him deal with the Crisis when the time comes.
In mid-2019, Team Flash, with the help of Nora West-Allen from 2049 and the manipulation of Eobard Thawne, managed to destroy Cicada's lightning dagger. Those actions resulted in many changes to the timeline, including the change of the date of the crisis from 2024 to 2019. This forced Novu to take action to prevent the crisis far sooner, causing him to pick up Oliver much faster than he initially told Oliver he would in order to have him complete missions to delay the crisis until his preparations are fully completed. Around that time, Novu looked into the future and found out Oliver will die during the crisis, which he told Oliver. He also destroyed the plinth in the Time Vault to prevent Team Flash from learning about the much faster crisis so that when the time came, he could tell them personally.
Novu also retrieved Lex Luthor's corpse and brought him back to life so he would use his intellect in the crisis but confined him in his realm apparently to prevent him from trying anything malicious.
Novu first sent Oliver to Earth-2 to retrieve Dwarf star particles. Although he experienced problems doing so because of Tommy Merlyn's mission to destroy the Glades using the Dwarf star particles, he eventually succeeded. However, due to him interfering with the events of the alternate Earth it was destroyed by a wave of anti-matter.
Displeased but still tolerating Oliver's tendency to let his feelings get over him, Novu brought Oliver, Diggle, and Laurel to Hong Kong and tasked them to find Dr. Robert Wong. Although Wong was retrieved, Oliver defied Novu by sending him to A.R.G.U.S but as Lyla Michaels was Novu's ally, the Monitor simply contacted her and she gave him Wong straight away.
Not concerned at all by Oliver's decision to defy and destroy him out a false belief that he was causing the crisis, Novu simply integrated Oliver's plans into his own and to reward Oliver's determination, he brought his kids and Connor Hawke from 2040 to the present day. Since Laurel was not supposed to have survived, Novu decided to test her next. He approached her and offered to restore her Earth if she betrayed Oliver. However, Laurel ultimately refused, which was Novu's plan originally. To reward Laurel, Novu put her and Oliver in an alternate reality where Laurel could say goodbye to Quentin Lance. The alternate reality also served to teach Oliver that he could not alter his fate.
Once both completed their tasks, Novu brought them to Lian Yu. Their goal on the island was to create a device to power a weapon. The device, however, only responded to Lyla's DNA. When she touched it, she suddenly had an epiphany and realized she had to go.
Team Flash's preparation
Around the same time, Novu went to S.T.A.R. Labs to inform Barry and Iris that Barry was now going to sacrifice his life on December 10, 2019. Now knowing about his upcoming death, Barry decided to prepare Team Flash for protecting Central City without him.
After preparing Killer Frost, Barry put his focus on Cisco Ramon, who he decided is the perfect guy to replace him as team leader after he is gone. Although at the beginning Cisco refused to accept Barry's death, he eventually learned to do so.
After that, Barry decided to promote Ralph Dibny to his successor as the official protector of Central City after his death, which he did after a mission to get more information on Sue Dearbon's disappearance.
J'onn J'onzz's test
Having witnessed J'onn J'onzz fight but knowing that he was plagued by his past, Novu traveled to Earth-38 and released J'onn's brother, Malefic, from the Phantom Zone. After multiple encounters between Malefic and the Superfriends, J'onn learned to make amends with both his past and brother, which eventually resulted in Malefic forgiving him.
Novu then returned to Earth-38 once J'onn had completed his test, claiming that he was now ready for the Crisis.
Harrison Nash Wells
On December 9 in Central City, Harrison Nash Wells, after having been attacked by a Blood Brother outside a door to what he believed was the Monitor's realm, was saved when Allegra Garcia used her powers to spread a cure to the city. Wells, however, misattributed this to Novu himself. At 11:58 pm, just as Nash was about to open the portal to his realm, a voice that sounded like Novu noted on how he wished to know the truth and offered to reveal to him what he wanted to know in exchange for his help stopping the Crisis. The voice told him to stop his attempts to kill him and begin, a new life. When Nash asked the voice to show him, he was told that he already has "the knowledge" (probably to solve a code). After Nash solved the code in the cave, the rock opened and pulled Nash inside it in a flash of light before slamming down the rock wall again. However, in doing this, Nash accidentally released the Anti-Monitor instead and became a Pariah.
As the Crisis began on December 10, the skies above Lian Yu, Central City, and possibly the entire planet began storming and turned red. On Mar Novu's command, Harbinger arrived on Lian Yu to retrieve Oliver and Mia. At midnight in Central City, Team Flash watches the skies turn red and prepare themselves for the upcoming battle.
Lyla then warped all the greatest heroes of Earth-1 to Earth-38, where Argo City had just been destroyed by an antimatter wave, and the heroes worked with the rest of Earth-38 heroes to evacuate as much of the universe's population as possible. As the battle between the heroes and the shadow demons of the Anti-Monitor continued to prove fruitless as more and more kept coming, the Monitor arrived to announce that the battle was lost and they must escape. Novu breached all but Oliver Queen, who immobilised him temporarily using an antimatter arrow and fought off the shadow demons long enough for 3 billion people to escape to Earth-1, although sustaining mortal injuries in process, until the Monitor teleported them to Earth-38, where Oliver said his last words to his comrades and daughter before dying, fulfilling Novu's prophecy of Oliver dying in the Crisis, but not the same way that Novu had foreseen. As the surviving heroes mourned the loss of their comrade, Harrison Nash Wells, now a branded a Pariah for his actions, teleported in garbed in a suit of green and gold armor, declaring that all was lost. Meanwhile, the Anti-Monitor's anti-matter wave continued to flood across the Multiverse, sowing massive chaos and instability and even causing the Pillars of Magic to crumble, effectively robbing individuals like John Constantine of the ability to use magic on a continuing basis.
Unable to match the Anti-Monitor's armies or raw power, Novu and Harbinger set up the remaining heroes on the Waverider of Earth-74 as a base of operations with that Earth's Mick Rory while the Earth-1 Legends remained on the front lines. Novu informed the shaken heroes that there existed seven Paragons; seven special heroes who each exemplified a particular heroic trait above all others. He named Sara as the Paragon of Destiny and Kara as the Paragon of Hope. On Earth-18, Sara, Barry, Mia, and John Constantine take Oliver's body to a Lazarus Pit in an attempt to resurrect him, but the accumulating anti-matter across the multiverse prevents them from bringing his soul back. Eventually, the remaining Paragons were located, with Ivy Town resident Ryan Choi as the Paragon of Humanity, Barry Allen as the Paragon of Love, Kate Kane as the Paragon of Courage, J'onn J'onzz as the Paragon of Honor, and Clark Kent as the Paragon of Truth. Unbeknownst to everyone, Harbinger is secretly contacted by the Anti-Monitor.
In trying to locate the Anti-Monitor's base of operations, Cisco Ramon, Caitlin Snow, and Barry, with the help of Pariah, discovered a hidden room within the Central City sewers that contained a treadmill which was the source of the antimatter wave. Barry soon realized that his counterpart from Earth-90 was powering the treadmill with his super-speed, being forced by the Anti-Monitor to do so against his will. After he was removed from the device by Cisco, Barry-90 warned that the multiverse would be destroyed entirely if he failed to continue powering the treadmill. In order to offset this destruction, Pariah brought Jefferson Pierce/Black Lightning to Earth-1, having him use his powers to temporarily contain the process. After it was revealed that in order to permanently stop the antimatter wave, a speedster would have to run in the opposite direction of the treadmill and die in the process, Barry-90 transferred Barry-1's speed to himself and did the deed, stopping the wave and averting Barry-1's foretold sacrifice albeit at the cost of his own life. Meanwhile, Constantine, Mia, and Diggle visit Lucifer on Earth-666 to get his help in entering Purgatory and retrieve Oliver's soul. Before they can leave, Jim Corrigan appears so he can bestow onto Oliver the Spectre's power. Oliver accepts, and Constantine's team is sent back to the Waverider without him. While the heroes regroup, the Anti-Monitor sends a brainwashed Harbinger to kill the Monitor so he can absorb his power and finish destroying the multiverse. Before the remaining heroes and Earth-1 are destroyed, Pariah sends the Paragons to the Vanishing Point to keep them safe, where they witness Lex replace Superman-96 with himself using a page from the Book of Destiny.
The battle at the Dawn of Time
In the months since the multiverse was destroyed, the Paragons have struggled to survive. Once Corrigan teaches him how to use the Spectre's power, Oliver heads to the Vanishing Point to rescue the Paragons and strengthen Barry's powers. With his increased speed, Barry drops off Kara, Choi, and Lex on Maltus, but gets attacked by the Anti-Monitor, losing everyone else across the Speed Force. Despite an expected double-cross from Lex, Kara, and Choi convince Novu not to go through with his plans. Once Barry retrieves everyone, they arrive at the dawn of time, only to learn the Anti-Monitor will always learn of the multiverse's existence no matter what, as there will always be a Novu in the multiverse who cannot give up his ambitions. The Paragons battle the Anti-Monitor and his shadow demons until Oliver uses the Spectre's power to restore the multiverse, with the Paragons providing additional assistance via Lex's Book of Destiny page. As a result however, Oliver dies a second and final time in Barry and Sara's arms.
A new universe
Waking up in the newly recreated universe, the Paragons discover they are the only ones who remember the Crisis and that both Earth-38 and Jefferson's Earth have been merged with Earth-1 into a composite universe later designated as Earth-Prime; among other changes throughout the multiverse. While J'onn uses his psionic powers to bring their allies up to speed, Sara attempts to find Oliver, though without success. Later that night, the Paragons are attacked by shadow demons. Upon finding a restored and remorseful Nash, he discovers that the Anti-Monitor is still alive and plotting to renew his destruction of the multiverse. To stop him once and for all, Nash, Ray, Barry, and Choi work to develop a bomb capable of shrinking the Anti-Monitor for eternity while the other heroes distract him. Once it's finished, Kara uses it on the Anti-Monitor and sends him to the microverse. Sometime later, Barry, Kara, Sara, Kate, Clark, J'onn, and Jefferson hold a memorial service for Oliver before agreeing to come together as a league of heroes to protect their new world in Oliver's memory.
In the newspaper that chronicled the Crisis, when the Crisis hit Earth-1, the battle to save it took place within Central City and included the likes of The Flash, Green Arrow, White Canary, Supergirl, Batwoman, and numerous other "legendary heroes" against the Reverse-Flash at midnight.
In an erased future, after his death, Oliver Queen was buried next to his father and his paternal half-sister, his tombstone will read that he was a "beloved husband, brother, father and son. Hero of Star City. The Green Arrow".
- "It's true! We all live on the same Earth now. Our Earths must have merged when we helped Oliver reboot the universe."
- —Barry Allen to Kara Danvers[src]
Following the Crisis, with the multiverse having been reborn, not everything remained the same, with many changes being evident, such as:
- Elements of Earth-1, Earth-38, and Earth-BL were recreated in Earth-Prime, to such a convincing extent that the Paragons, who are natives of the former two, consider the worlds to have merged, as do Earth-Prime natives who hold the memories of a doppelgänger from one of these universes. In this regard, Barry Allen and Kara Danvers were only able to tell the difference when they encountered each other in National City, and Sara Lance could not tell the difference at all until Ray Palmer expressed surprise that Supergirl had had her own Earth.
- Earth-2, Earth-9, Earth-12, Earth-19, and Earth-96 have all been restored.
- L-Corp was erased from existence, and Lex Luthor is still the owner of Luthor Corp, as well as the Department of Extranormal Operations, which is now a subsidiary of LuthorCorp.
- Lex Luthor is seen by the public as a good person on Earth-Prime.
- The reincarnated John Diggle and Lyla Michaels now have two children: Sara Diggle originally from the Earth-1 pre-Flashpoint timeline, and John Diggle, Jr. originally from the post-Flashpoint timeline, instead of only having one child or the other.
- Rather than having just one son (Jonathan Kent), Lois Lane and Clark Kent have at least two children that are male.
- The universes are clearly not separated in the same way they were in the old multiverse, as Querl Dox was unable to detect the other universes through their vibrational frequency.
- Instead of not being able to use her sonic scream after getting her throat slit  as using it inflicts pain, Dinah Drake has had her powers restored to its full extent (at least as of 2040) as she was seen using them in the future. 
- Rather than witnessing the death of his mother at the hands of Slade Wilson, Oliver manages to save Moira Queen. Additionally, Tommy Merlyn, Emiko Adachi, and Quentin Lance are alive by 2020, and do not meet the same fate as in the original multiverse.
- Tommy married Laurel Lance, however, she would still die at some point prior to the Crisis.
DC's Legends of Tomorrow
- While it is well-documented that Eobard Thawne wasn't able to return to his time period after killing Nora Allen and thus had to spend the next 15 years of his life in the 21st century, the fate of the future Flash that followed him back from 2024 is still unclear after saving his younger self from Thawne.
- The photograph depicting the Flash on the newspaper article shows the Flash's suit in 2024, with a bright red suit with red earpieces and a white outline on the emblem. In an erased future of 2024, the Flash suit bears a closer resemblance to his fourth suit. However, that future was erased when Team Flash erased Savitar from existence on May 24, 2017.
- In the original time of the Crisis, meta-humans like the Flash still operated in 2024, despite the Anti-Meta-human Act of 2021, which apparently makes it illegal to even be a meta-human.
- Due to Oliver Queen and his team being deputized by the SCPD in 2018, it stands to reason that they and several of the other heroes present were working alongside local law enforcement and possibly even A.R.G.U.S. and were no longer considered "vigilantes".
- The only individuals that weren't affected by the changes created in the new multiverse and have retained their memories are the Paragons (Barry Allen, Kara Danvers, J'onn J'onzz, Kate Kane, Lex Luthor, Ryan Choi) and others such as Jennifer Pierce, Lena Luthor along with several orphans from other Earths survived the destruction of the old multiverse through other means.
Behind the scenes
- Nora West-Allen traveled back to the present day and revealed more about this crisis event by bringing in a newspaper from 2049. This newspaper shows that this crisis event is similar to the comic book event Crisis on Infinite Earths. This is due to the appearance of characters such as Roger Hayden a.k.a Psycho-Pirate and shadow demons, both of which appeared and played a relatively important role in the DC comic book event.