The Arrowverse has had several crossovers already, and ranking them is no easy task. The CW's shared superhero universe officially kicked off when The Flash joined the flagship series, Arrow, in 2014. The next series, DC's Legends of Tomorrow, gave a new home to the Arrowverse's many outcast heroes and villains while opening up time travel. In 2016, Supergirl jumped from CBS and joined the Arrowverse and, in 2019, Batwoman becomes the latest series in the pantheon as Arrow enters its eighth and final season.
The Arrowverse has become so expansive that Crisis On Infinite Earths is expected to be a reckoning for the Multiverse. Based on the 1985 DC Comics mega-event, Crisis On Infinite Earths promises to end worlds and could possibly meld the Arrowverse together as one cohesive universe. But by the time Crisis On Infinite Earths comes around, the Arrowverse's superheroes, led by the Trinity of Green Arrow (Stephen Amell), The Flash (Grant Gustin), and Supergirl (Melissa Benoist), have accumulated a ton of experience jumping Earths for team-ups and saving the universe. Indeed, the supporting casts of all of Arrowverse's series have met each other, become friends, and, when called upon, can combine their myriad talents and abilities to battle whatever supervillain or alien conquerors that come calling. But, this being the Arrowverse, sometimes, they just get together to sing and dance.
Whether it's an all-hands-on-deck assembly of every superhero or just Supergirl and the Flash joining together for a team-up by themselves, the Arrowverse's crossovers are not only a calling card of their shared universe but they're DC TV's equivalent to the Marvel Cinematic Universe. While there's really no bad Arrowverse crossover, here they are ranked worst to best.
7. Heroes Join Forces (2015)
Heroes Join Forces was what the two-part crossover in the 8th episodes of The Flash season 2 and Arrow season 4 was dubbed. Also known by the episode titles "Legends of Today"/"Legends of Yesterday", the crossover sets up the debut of DC's Legends of Tomorrow. Hawkman (Falk Hentschel), Hawkgirl (Ciara Renée), and their immortal enemy Vandal Savage (Casper Crump) are introduced, as is the history of Savage killing the Hawks throughout time so that they can reincarnate. Jax Jackson (Franz Drameh) also debuts as the new half joining Martin Stein (Victor Garber) as Firestorm. Another important figure introduced is Oliver Queen's young son William.
While jam-packed with DC Comics heroes, the 2015 crossover is usually forgotten since Legends of Tomorrow season 1 is poorly regarded overall. In addition, many of the key characters here, like Hawkman and Hawkgirl, were unpopular and have been banished from the Arrowverse.
6. Flash Vs. Arrow (2014)
After Barry Allen debuted in Arrow season 2 and Oliver Queen paid it back by appearing in The Flash's pilot, Flash Vs. Arrow is the first official crossover in the Arrowverse. However, it's actually two episodes: The Flash episode 8 "Flash Vs. Arrow" and Arrow episode 8 "The Brave and the Bold" featured separate storylines involving The Rainbow Raider attacking Central City and Captain Boomerang running amok in Starling City. The fun of Flash Vs. Arrow was Team Flash and Team Arrow venturing to each other's city and meeting for the first time, which established the Cisco Ramon (Carlos Valdes)/Felicity Smoak (Emily Bett Rickards) dream team and introduced John Diggle's (David Ramsey) extreme discomfort at the fact that metahumans like the Flash now exist in the world.
Flash Vs. Arrow solidified the mutual respect/rivalry between Barry and Oliver as the Arrowverse's Big Two, which culminated in their Rocky III-inspired showdown to find out which of them was really the better superhero. Most importantly, Flash Vs. Arrow proved the Arrowverse is a cohesive a shared universe and opened up the tantalizing possibilities to come.
5. Elseworlds (2018)
The 2018 crossover spanned Arrow, The Flash, and Supergirl but it was the Arrowverse's most ambitious event yet. Elseworlds busily introduced Jeremy Davies as John Deegan and LaMonica Garrett as The Monitor, who used the Book of Destiny to test and destroy worlds in the Multiverse for the upcoming Crisis. Oliver Queen and Barry Allen switched bodies, forcing them to take on each other's superhero identities, and only Supergirl could see the truth. What's more, Elseworlds brought back Superman (Tyler Hoechlin) and introduced Lois Lane (Elizabeth Tulloch), the Kent Farm from Smallville, and the evil Black Suit Superman for the heroes to fight, plus John Wesley Shipp's version of The Flash also makes an appearance. If that isn't enough, the second hour took the heroes to Gotham City and introduced Batwoman (Ruby Rose) and the supervillains imprisoned in Arkham Asylum, setting up the new Batwoman series.
By trying to accomplish so much, Elseworlds was jam-packed with characters and superhero action but it didn't quite all gel together as a satisfyingly cohesive story, despite the excellent work by Stephen Amell and Grant Gustin, who amusingly played the Flash and Green Arrow, respectively. Ultimately, bigger didn't mean better and Elseworlds ends up as the chaotic bridge that leads to the conclusion of Arrow and 2019's Crisis On Infinite Earths crossover.
4. Invasion! (2017)
Inspired by the 1989 DC Comics event, Invasion! united Team Flash, Team Arrow, and the Legends of Tomorrow while bringing Supergirl to Earth-1 for the first time after her series jumped from CBS to The CW. Together, the superheroes battled an invasion by the alien Dominators, but the middle portion was also Arrow's 100th episode, which brought back Arrow's dead characters like Katie Cassidy as Laurel Lance and Susanna Thompson as Moira Queen in a dream reality created by the aliens. Meanwhile, the characters were dealing with the new status quo that emerged from Barry altering the timeline after he created the Flashpoint reality, so that Cisco's brother was dead and John Diggle's daughter became his son.
Still, seeing Supergirl interact with her fellow superheroes for the first time was a delight, capped off by the Arrowverse acknowledging Brandon Routh's time playing Superman for the first time - which will pay off when the actor portrays Kingdom Come Superman in Crisis on Infinite Earths. Invasion! also debuted the abandoned STAR Labs hangar that resembles the Super Friends' Hall of Justice and made it clear that, with Supergirl readily available to cross over from her Earth-38, that the Arrowverse was truly a Multiverse.
3. Duet (2017)
Duet took place in a single episode of The Flash season 3 but it also involved Supergirl, Mon-El (Christopher Wood), and J'onn J'onzz (David Harewood), as well as Legends of Tomorrow's Victor Garber and Arrow's John Barrowman. After an alien called the Music Meister (Darren Criss) leaves Supergirl in a coma, he escapes to Earth-1 and does the same to the Flash - which traps both Barry Allen and Kara Danvers into a dream reality that has the rules of a 1930s gangster musical. Duet delightfully takes full advantage of Melissa Benoist and Grant Gustin being former cast members on Glee but also showcases the musical talents of the Arrowverse actors who have appeared on Broadway, like Carlos Valdes, Jesse L. Martin, Jeremy Jordan, as well as Garber and Barrowman.
A heartfelt exploration of love that examines the complicated relationships between Kara/Mon-El and Barry/Iris West (Candice Patton), Duet is one of the finest musical episodes of a TV series ever made. This is thanks to the songwriting teams behind La La Land and Crazy Ex-Girlfriend, but Duet also proved the fate of the universe didn't have to be at stake to have a thoroughly enjoyable Arrowverse crossover.
2. World's Finest (2016)
Supergirl season 1 was originally on CBS so the Flash joining her on Earth-38 for an episode was the first-ever dual-network crossover in the Arrowverse that also established the Girl of Steel as part of The CW's Multiverse - and this set the stage for Supergirl to jump to The CW for season 2. Crucially, World's Finest is an immensely entertaining superhero team-up that showcased the winning interplay between Melissa Benoist and Grant Gustin. When the Flash accidentally jumped to Earth-38, he meets Kara Zor-El and her CatCo workmates, including a jealous James Olsen (Mehcad Brooks), Winn Schott (Jeremy Jordan), and Cat Grant (Calista Flockhart).
Supergirl's enemies Silver Banshee (Italia Ricci) and Live Wire (Brit Morgan) also teamed up to take on the Girl of Steel and the Scarlet Speedster, who amusingly one-up each other with their crimefighting methods. More important is how smoothly Gustin's Barry and Benoist's Kara mesh as their real identities and together, they opened the door for Supergirl to fully join the Arrowverse and take her place alongside Flash and Green Arrow as part of the Trinity.
1. Crisis On Earth-X (2017)
Spanning all four series, Crisis On Earth-X is the gold standard of Arrowverse crossovers, made all the more impressive by the fact that it aired at the same time Justice League was in theaters and The CW's event was, by far, the better and more satisfying DC Comics super team-up adventure. When all of the superheroes gathered in Central City for Barry and Iris' wedding, they are attacked by their Nazi doppelgangers from Earth-X led by Dark Arrow (Stephen Amell), Overgirl (Melissa Benoist), and the Reverse-Flash (Tom Cavanaugh). The Nazi villains attempt to kidnap Supergirl and steal her heart to replace the dying Overgirl's and this results in the superheroes being trapped in the brutal world of Earth-X and having to fight their way back home.
Martin Stein heroically sacrificed his life to save his fellow heroes, which lent the crossover genuine stakes, and the final battle between the superheroes and the Nazi army of Earth-X is one of the best showdowns ever in the Arrowverse. This is made even better by Supergirl quoting Superman II in a challenge to Overgirl: "General, would you care to step outside?" By the end of the crossover, not only are Barry and Iris married but so are Oliver Queen and Felicity Smoak. While the Nazi subject matter remains controversial, Crisis On Earth-X is a bold and spectacular Multiversal adventure that sets a high bar for Crisis On Infinite Earths to match.