In recent years, the DCEU seemed to be defined by rushed attempts to capitalize on the shared movie universe that the MCU leaned into with its superhero properties. In that regard, it has yet to find its footing, though upcoming films may prove more successful at creating a more definitive whole for DC film franchises. However, the television-based Arrowverse is a different matter.
Like the MCU, the CWVerse laid the foundation for its shared continuity gradually, show by show, from Arrow to The Flash, and so forth. In doing so, it has endured and flourished, treating fans and newcomers to mostly effective realizations of DC Comics' characters and allowing them to participate in regular crossover specials. These events have grown and varied in size and scope since the first one aired, with some naturally being better received than others.
Heroes Join Forces
The immortal Vandal Savage arrives in Central City seeking his reincarnated self-proclaimed love, Kendra Saunders, a.k.a Hawkgirl. To protect her and her true lover, Hawkman, the Flash joins forces with Green Arrow to defeat Savage.
This was only the second major crossover between The Flash and Arrow, and it was weighed down by its obligation to setting up the first season of Legends of Tomorrow. Still, it contributed to Green Arrow's story by involving Oliver Queen's illegitimate son, giving us more set-up for future Arrow plot lines. The climax seemingly had the heroes lose only for Barry Allen to deus ex machina his way to victory through time travel.
World's Finest
It is debatable whether this counts as an event. At a time when Supergirl was still owned by CBS, the Flash accidentally speeds his way into Kara Danvers' world and ends up helping her with the latest superhuman threats affecting her fair National City.
This single episode crossover was significant in establishing the charming chemistry between Melissa Benoist and Grant Gustin before Supergirl's migration to the CW. It otherwise functioned as just another episode of Supergirl that managed to rope in Barry Allen as a special guest star.
Armageddon
-1.jpg?q=50&fit=crop&w=1500&dpr=1.5)
This special had a monumental challenge before it. Not only was it the first multi-episode crossover following the massive Crisis on Infinite Earths event, it was also the first one done without Oliver Queen after the conclusion of Arrow, the CWVerse's progenitor. While the title implied high stakes, this was more of a personal story for Barry Allen.
The alien Despero, played wonderfully by Tony Curran, appears from the future to kill Barry as he apparently loses his mind at some point and brings about the world's destruction. While the Flash was very much the central focus, various characters from across the CWVerse made welcome appearances throughout, and Despero was presented as a threatening and complex new antagonist for the Scarlet Speedster. The initial mystery surrounding Barry's supposed descent into madness was also quite engaging, even if the overall story dragged at points and certain elements felt all-too-familiar.
Duet
Like "World's Finest", this second crossover between The Flash and Supergirl was limited to one episode. Unlike its predecessor, however, "Duet" could reasonably be called an event because of its refreshing musical format. The Music Meister, played by former Glee actor, Darren Criss, traps Barry and Kara in a song-and-dance dreamworld populated by doppelgangers of their friends and family.
The episode took full advantage of the musical abilities of its two main stars, both also Glee alumni, and those of its supporting players, which included the likes of Jesse L. Martin, John Barrowman, Victor Garber, and others, in a super flashy production and plot worthy of its Broadway talent and influences.
Invasion!
This was the CWVerse's first grand crossover, assembling characters from Arrow, The Flash, Legends of Tomorrow, and Supergirl to combat a global extraterrestrial threat called The Dominators. While having all of these heroes interact, butt heads, and join forces for the first time was certainly rewarding, special attention was given to Barry Allen and Oliver Queen.
Barry is forced to confront the fallout from the "Flashpoint" storyline and the reactions of his friends and allies upon them learning of his actions. One of the few to stand by him is Oliver, whose morally complicated background enables him to understand Barry's choices. Speaking of Oliver, the second part of the crossover also served as Arrow's 100th episode, allowing for a celebration of the show's history up to that point, with some notable guest appearances, all wrapped up in a larger battle against hostile invaders.
Flash Vs. Arrow
-1.jpg?q=50&fit=crop&w=1500&dpr=1.5)
Sometimes, simplicity is best. The first official crossover event between the CWVerse's flagship shows may lack the bold vision of later efforts, but the smaller scope allowed for more intimate storytelling, as the two leads try to help one another overcome a villain plaguing each of their home cities.
The underappreciated brilliance of this crossover was how it examined the differences between its polar opposite heroes. The idealistic Flash struggles to comprehend the grittier Green Arrow, leading to insightful and entertaining interactions between the two as they alternate between working with and against each other.
Elseworlds
This major crossover was notable in that it served as a prelude to a bigger event down the line. One day, Oliver and Barry inexplicably find themselves living each other's lives. With the help of Supergirl, they discover that they are part of a trial orchestrated by The Monitor, a mysterious cosmic being who seeks to prepare them for a coming cataclysm.
In addition to the wildly entertaining concept of Stephen Amell and Grant Gustin swapping superhero identities, this event provided the introduction of Batwoman, as well as the return of John Wesley Shipp as the Barry Allen from the short-lived '90s Flash show. This three-parter was just pure fun, following the CWVerse Trinity as they jump from the Smallville farm to Gotham City to a battle with an evil Superman, with tons of Easter eggs and callbacks sprinkled in. And yet, it ends on an ominous note, promising lasting consequences for the future.
Crisis On Infinite Earths
This was the Avengers: Endgame of the CWVerse. Every major hero from every show is called to help stop the annihilation of the multiverse at the hands of the Anti-Monitor. The scope of this crossover was practically unprecedented for television. Numerous guest stars came in to reprise their roles from multiple DC properties across different mediums. From Tom Welling to Kevin Conroy to Ezra Miller, the fanservice was jaw-dropping. And the stakes were appropriately colossal. By the end of it all, the heroes' worlds were shaken in ways that they would struggle to recover from.
The death toll was staggering, but such that it was impossible to believe that the devastation would not ultimately be undone. The final battle between a handful of heroes armed with one-liners against a faceless army was sinfully underwhelming, saved only by the weight of Oliver Queen's fateful showdown with the Anti-Monitor. If the story had matched the ambition, this would have been an absolutely perfect crossover event.
Crisis On Earth-X
-Cropped.jpg?q=50&fit=crop&w=1500&dpr=1.5)
The excuse for gathering heroes from multiple shows together here began as a happy one, and that was the wedding of Barry Allen and Iris West. Then, wedding crashers showed up in the form of Nazi doppelgängers from another Earth.
This crossover has it all: A compelling and tightly-paced plot, exhilarating and varied action sequences, memorable appearances from characters both new and familiar, and gut-wrenching emotional impact underscored by the death of a longtime regular. Nothing more need be said to justify this one's title as the best of the CWVerse's crossover events.