"Crisis on Infinite Earths" is the sixth Arrowverse crossover event, featuring episodes of the television series Supergirl, Batwoman, The Flash, Arrow, and Legends of Tomorrow on The CW.

In "Crisis", the Monitor gathers Green Arrow, the Flash, Supergirl, Batwoman, Sara Lance, Ray Palmer, and several others from throughout the multiverse to stop the Anti-Monitor from destroying reality.

"Crisis on Infinite Earths" was intended to be followed by a crossover between Batwoman and Superman & Lois in 2021,[1] but this did not occur because of the COVID-19 pandemic,[2] being replaced informally by David Ramsey appearing as John Diggle on multiple Arrowverse series.

[4] To prepare for the coming crisis, the Monitor recruits Oliver Queen and Martian Manhunter and sends the former on missions to collect a variety of items,[5] while he retrieves the body of Lex Luthor and revives him.

[10] In Star City, William Clayton, Connor Hawke, and Mia Smoak time-travel from 2040 to the present,[11] while Oliver and John Diggle learn that Lyla Michaels has been working with the Monitor.

Brainiac 5 detects the wave approaching Argo City, prompting Kara Danvers to warn her mother Alura Zor-El, her cousin Clark Kent, and his wife Lois Lane.

Kara and Kate travel to Earth-99, but fail to recruit its Batman after discovering he murdered his world's Superman while Sara, Barry, Mia, and John Constantine take Oliver to a Lazarus Pit on Earth-18 in an attempt to resurrect him, only to learn his soul is missing.

[81] The end of "Elseworlds" revealed the crossover title and premise as "Crisis on Infinite Earths", adapting the story from the 1985 comic of the same name by Marv Wolfman and George Pérez.

[85] In May 2019, Pedowitz announced at The CW's upfront presentation that the crossover would include The Flash, Arrow, Supergirl, Legends of Tomorrow, and Batwoman in a five-episode event spanning late 2019 and early 2020.

[91] Guggenheim said that when they first presented the crossover to the studio and network, the creators stressed that they did not want the event to be "Crisis on CW Earths" but "to touch as many strands of the DC tapestry as possible".

Its four main characters are Felicity Smoak, the Ray, Nyssa al Ghul, and Wally West, in addition to appearances by Atom, Sara Lance, Batwoman, the Flash,[100] the Monitor, Lex Luthor, and others.

[101] Wolfman added that the comics were "created to tie in perfectly with The CW shows" so it felt like a main part of the story and not ancillary:[100] "This is integral to the entire storyline".

According to Wallace, this gave "it a nice story twist, [to] get in some emotion" while "complet[ing] a 30-year arc" for John Wesley Shipp's character, who felt thankful in turn as his show didn't get a proper series finale.

[49] Pedowitz announced at the Television Critics Association press tour the following month that cast members from Black Lightning would appear[91] (previously hinted at by Cress Williams),[133] and Kevin Conroy would portray an elderly Bruce Wayne after voicing the character in multiple animated media.

[65] Osric Chau was cast as Ryan Choi later in the month, and Ashley Scott was confirmed as reprising her role as Helena Kyle / Huntress from The WB series Birds of Prey.

There were "a whole host of reasons why" certain cameos did not occur, according to Guggenheim, as some actors were busy with other projects, some were uninterested in the crossover and others requested more money than the budget permitted, while the showrunners also had to think on those characters' screentime, their requirements in the story and the shooting schedule.

[112] Directors of the crossover included Jesse Warn (Supergirl),[104] Laura Belsey (Batwoman),[23] David McWhirter (The Flash),[37] Glen Winter (Arrow),[34] and Gregory Smith (Legends of Tomorrow).

[29] After the crossover, Dries wanted to "make Kate's life a little bit more integrated with all of this madness of sci-fi and aliens, and the dense mythology between" the other series, but still keep the grounding established earlier in Batwoman's season.

[35] A behind-the-scenes panel moderated by Guggenheim and featuring The Flash first assistant director Phil Chipera, Batwoman costume designer Maya Mani, Legends of Tomorrow property master Lynda Chapple, and Arrowverse senior visual effects supervisor Armen Kevorkian, was part of DC FanDome in September 2020.

[191] A theatrical release of the crossover had been planned in coordination with Warner Bros. and Fathom Events for April 2020 in the United States, which would have involved cast appearances, giveaways, and the inclusion of additional material between the episodes such as deleted scenes with completed post-production.

The website's critical consensus reads: "TV's biggest crossover manages to tie these different universes together, offering plenty of cameos, dramatic moments, and surprising twists that will shake the Arrowverse forever.

He felt that the Supergirl supporting cast was "utilized well" and called the episode "very critical" for fans of Arrow, given Oliver's death, although he regretted Barry's small role.

About the cast, Burt said: "By keeping the ensemble in this part of the story relatively small, we were able to spend more time with all of them, not to mention check in with the characters who are Supergirl-specific"; "one of the best scenes" was between Alex and Lena.

The website's critical consensus reads: "Part two of DC's ambitious crossover is just as relentless as the first installment, if even smoother around the edges, masterfully juggling many characters, emotions, and Easter eggs to a satisfying result.

"[211] Schedeen called the episode "a superhero nerd's dream come true", since it "doubles down on the emotional character drama and manages to deliver some of the best live-action Superman moments in a very long time."

The website's critical consensus reads: ""Crisis on Infinite Earths"'s fourth installment reshuffles the universe in rousing fashion thanks to Arrow himself and a delightful cameo from Ezra Miller, even if repeating the same sacrifice twice dilutes the impact of this farewell to Oliver Queen.

Concerned that the crossover would buckle under its own weight in part three, Schedeen was glad in the Arrow episode that its "consolidating [of] the cast down to a handful of heroes and a few cosmic entities really help[ed] refocus and remind viewers of what's at stake."

Giving the episodes 4 out of 5 stars, she concluded: "For those of us who were touting Arrow as the best superhero property on any screen, big or small, back in Season 1, this is truly the television equivalent to Endgame-level storytelling.

Kulzick was disappointed that the Monitor and Anti-Monitor's godlike powers were poorly explained, and called the Speed Force moments "arbitrary" in what could have been "a wonderful opportunity to relive and re-imagine high points from each of the Arrowverse shows' histories."

[228] Entertainment Weekly helped develop the aftershow, which included discussions with executive producers Guggenheim, Dries, Rovner, Shimizu, and Wallace; the stars Cryer, Garrett, McNamara, and Conroy; and panel guest Dani Fernandez, among others.