While the DCEU version of The Flash is finally getting his own solo film in 2022, he's already had several appearances across multiple DC film and tv projects. Ranging from minor cameos to starring roles with ensemble casts, Ezra Miller's Flash certainly gets around. While this can largely be attributed to Miller's love for the role, it seems as though their character is one Warner Bros. has the least problem giving the green light to for appearances big and small. As such, Barry Allen has become the lynchpin in DC's attempts to connect its cinematic universe.
Beginning with Batman v Superman: Dawn of Justice, Ezra Miller's take on Barry Allen first featured among a list of their metahumans Batman recovered, precluding the formation of the Justice League. What followed has been a collection of cameos aside from Justice League and Zack Synder's original vision for the 2017 film. The Flash has had the most appearances out of any other DCEU hero, being featured in four movies and two television series (and has even crossed universes as well).
While it will certainly be exciting to see Miller's Flash finally in their own solo film from director Andy Muschietti, the odds are strong that the average audience member will have already been introduced to this version of Barry Allen in some capacity beforehand. This could certainly be a strategic move on Warner Bros.' part, taking a page from Marvel Studios and their methods of introducing new characters, though it could also be more coincidental due to production delays along with DCEU uniquely having their large team-up film before the majority of its solo films were released. Nevertheless, Barry Allen's unique abilities, coupled with Warner Bros.' clear desire to create a single, interconnected story in the vein of the MCU, have meant that The Flash has featured far more than any other cinematic DCEU hero. As such, here's every appearance of the DCEU's Flash before his own movie.
Batman v Superman- Luthor's Files & The Flash From The Future
In 2015's Batman v Superman, Barry Allen's debut was part of the collected files Lex Luthor had gathered on metahumans which eventually fell into the hands of Batman (courtesy of Wonder Woman). Featured in surveillance camera footage stopping a convenience store robbery in a matter of seconds, Barry's speed was immediately on display. However, Barry Allen's other appearance in Dawn of Justice was far more complex in a scene that will likely never be paid off by Warner Bros.
While Batman was decrypting the aforementioned metahuman files, he fell asleep. What followed was the surprising "Knightmare Sequence" which teased the future envisioned by director Zack Snyder where Darkseid would have taken over the world in future Justice League films. However, Batman was woken up by what appeared to be an armored Flash from the future, carrying dire warnings of what was intended to come next, telling him to "find the others". While Warner Bros. has largely pivoted away from Zack Snyder's vision that was presented in Dawn of Justice, Barry Allen's appearance is still a significant demonstration of his potential power. Not only does it tease the interconnectedness of the DCEU's different narrative threads, but it also established The Flash's time-traveling potential and it's possibly significant future role.
Suicide Squad- Flash Stops Captain Boomerang
Barry Allen's next appearance would be in 2016's Suicide Squad from director David Ayer, featuring the government's covert ops team of super-criminals run by Director Amanda Waller. While the majority of the team's villains were traditionally Batman rogues such as Harley Quinn, Deadshot, and Killer Croc, Task Force X also featured Captain Boomerang who's typically a Flash foe in the comics. Seeing as how Ben Affleck's Batman had cameos bringing his villains to justice, it only made sense for the Flash to have his own cameo to take down Boomerang. This cameo in Suicide Squad was also the debut of The Flash's first suit, and the sequence was also filmed by Zack Snyder rather than Ayer on the set of Justice League (which was in the midst of production at the time). This not only laid the groundwork for things to come in the so-called Snyder-verse, but further cemented The Flash's credentials as a ubiquitous franchise presence.
Justice League/Zack Snyder's Justice League- Flash Needs Friends
Barry Allen's most prominent role thus far has been alongside DC's other heroes in 2017's Justice League, recruited by Batman to join the team he built to combat the forces of Apokolips. While Bruce Wayne struggled to recruit Aquaman to his cause, getting The Flash to join him couldn't have been easier. Barry had already decided that he needed more friends, meaning he was more than willing to join up after hearing that Batman needed his help.
2021 also saw Zack Snyder's original vision for Justice League being released on HBO Max, featuring a somewhat different version of Barry Allen. While the theatrical release saw Barry Allen unsure of himself and receiving guidance on how to be a hero from Batman, Zack Snyder's Justice League saw the Flash as far more confident who had already been experimenting with his powers (such as time-travel). This was something that wasn't touched on in the original cut, and it arguably made Barry Allen the Snyder Cut's most changed hero between the two versions. However, both films leaned on the character's capacity for comic relief, giving a sense of what a solo project could feel like.
Crisis on Infinite Earths- Movie Flash Meets TV Flash
One of Barry Allen's most exciting cameos was in the Arrowverse's Crisis on Infinite Earths in 2019. The biggest and most anticipated crossover between all of DC's various television shows on the CW, Ezra Miller's Flash met the Arrowverse's Flash played by Grant Gustin as he traveled the multiverse. While only a brief sequence lasting about a minute and a half, The Flash of the DCEU and The Flash of the Arrowverse were given the chance to interact, an incredibly secretive sequence that was orchestrated by select DC creatives and producers after the crossover had already finished production. It was also a significant moment for the DCEU continuity as it was heavily implied that Miller's Barry was given the idea to be called "The Flash" from Gustin's Barry. This further fleshed out the DCEU version's character while demonstrating the multiversal potential of the entire franchise.
Peacemaker- The Justice League Arrives Too Late
Last but not least, the most recent appearance of the DCEU Flash was alongside Aquaman, Wonder Woman, and Superman in the season finale of Peacemaker starring John Cena. While the Justice League heroes were called in to save the day from the invading aliens known as the Butterflies, Peacemaker and his team had hilariously taken care of everything by the time they arrived. While Wonder Woman and Superman were kept in the shadows and played by stand-ins, Jason Momoa and Ezra Miller were actually featured as Aquaman and Flash. Furthermore, director James Gunn revealed that he originally thought he'd only be able to get Momoa until he heard that Miller was a big fan of his work and was willing to make an appearance as well. Furthermore, Ezra Miller's most recent cameo was actually filmed on the set of Guardian of the Galaxy Vol. 3 (also directed by Gunn). While perhaps not his most narratively significant intervention, Barry Allen's appearance further strengthens the link between all DCEU projects, both on the small and big screen.
Why The Flash Keeps Appearing In The DCEU
All in all, The Flash makes for a pretty great cameo role across all of these different DC projects. While Warner Bros. is clearly on board with greenlighting appearances from Ezra Miller's Barry Allen to create a greater connected universe, the regularity with which the DCEU's Fastest Man Alive shows up can likely be attributed to Miller's own willingness and evident love for Barry Allen. However, there's more to the frequency of his appearances than Miller's own enthusiasm.
It's clear that, from the powers he has displayed since his inception, Barry Allen is the ideal candidate for universe and timeline-hopping adventures. Therefore, with this long-established history, it makes canonical sense that he would be the character to show up and lend a sense of cohesion to the otherwise disparate DCEU. Not only do the appearances of Ezra Miller's Flash please Warner Bros.' executives, they also make sense within the DCEU's established rules, which is satisfying for audiences. Given this, and ahead of his starring role in The Flash, it makes total sense that The Flash has such a significant role in the DCEU.
