Summary
The Flash's only encounter with a Flash villain in the DCEU is in a Suicide Squad cameo, where he defeats Captain Boomerang in a flashback scene.
The DCEU failed to delve into The Flash's character beyond his involvement in the Justice League, prioritizing crossover movies over establishing standalone ones. This missed chance to incorporate the Flash's iconic adversaries in the DCEU disregards the potential for further development of the hero's rich comic book heritage.
The Flash in the DCEU was largely limited to his role in Justice League and did not have the opportunity to explore his own story in solo movies. Despite starting with Superman's origin in Man of Steel, the DCEU quickly released crossover films like Batman v Superman: Dawn of Justice and Justice League without gradually setting them up with individual character movies. Wonder Woman had her own film in between Batman v Superman and Justice League, but Aquaman and the Flash only had their standalone films after the first Justice League mission. Batman and Cyborg never got their own films. While Barry Allen had a significant role in Justice League and received his own movie before the end of the DCEU, the franchise barely delved into the Flash's rich DC lore. The only time in the DCEU that Ezra Miller's Barry Allen encounters a proper Flash villain is in the 2016 film Suicide Squad, as pointed out by a fan on Twitter (@Impulse785).
The DCU's Flash Needs To Use Flash's Famous Rogues Gallery
During a bank heist prior to the formation of Task Force X, Captain Boomerang is apprehended and sent to Belle Reve prison by Barry Allen. This moment in Suicide Squad serves as the introduction of the Flash's superhero suit in the DCEU, as well as his first encounter with a member of his notorious rogues' gallery. Subsequently, the Flash joins forces with the Justice League to combat Steppenwolf and the Parademons. In addition, in the 2023 film The Flash, the Flash squares off against General Zod, Faora, Nam-Ek, and Dark Flash.The Flash, a key character in the DCEU, plays a significant role in both cuts of Justice League and has a powerful influence on the multiverse in The Flash. However, the character's potential is undermined by the limited screen time given to Barry Allen's supporting characters and the absence of his iconic comic book enemies in the DCEU. Despite the numerous Flash villains that could have contributed to the development of Barry Allen's corner of the DCEU, including notable ones like Captain Cold, Gorilla Grodd, and Killer Frost, as well as more obscure antagonists such as Sand Blaster and Colonel Computron, none of them have made an appearance in the DCEU.
The Flash's rogues' gallery rivals that of Batman and Spider-Man in its sheer diversity. While some villains like Captain Cold, Heatwave, and Weather Wizard share a common theme, others vary greatly in terms of power and abilities. While harmless nuisances like Ragdoll and Papercut barely concern the Flash, formidable foes like Abra Kadabra and Godspeed can make his life a living nightmare.
Numerous popular Flash storylines showcase a wide range of DC villains that have yet to appear in movies. "Rogue War," for example, centers around a conflict between all of the Flash's adversaries, with Wally West caught in the middle. Likewise, "The Return of Barry Allen" and "Flashpoint" follow the respective battles of Wally West and Barry Allen against their archenemies, Professor Zoom and Reverse-Flash. With Reverse-Flash absent from Andy Muschietti's "The Flash," there may be an opportunity for the DCU to introduce him and set the stage for a complete and formidable rogues' gallery for the scarlet speedster on the big screen.
Source: @Impulse785/Twitter