When Supergirl moved from CBS to The CW, it not only gave The CW a whole new superhero show - it provided them with a cornerstone for their DCTV properties. Unfortunately, we know from Season 1 that Supergirl exists in a completely separate universe to The Flash, Arrow, and Legends of Tomorrow. In spite of this, The CW is committing to crossovers - and announcements at SDCC show real promise...
What Was Announced at SDCC?
Marc Guggenheim confirmed that the Girl of Steel will be appearing as a guest-star in all of the other DCTV shows on The CW. He explained:
"It’s an external threat from outside the shows that will involve Supergirl coming over to "The Flash," then "Arrow" then "Legends of Tomorrow."
The comment's a fascinating one, because it suggests that the villain in question won't be a part of either reality - not the Flarrowverse, nor Supergirl's. In other words, this unknown enemy will threaten not one but two realities - perhaps more - and the superheroes will be forced to work together to stop it.
Over in the comics, DC has a habit of using multiversal plots to straighten out their continuity, at times even merging realities at a whim. The most famous was Crisis on Infinite Earths, in which the villainous Anti-Monitor threatened the entire Multiverse. DC revisited the idea as recently as last year's Convergence miniseries, which united the superheroes of different realities against Brainiac.
The CW is essentially in the same position that DC has historically found itself in - with awkward continuity, franchises separated and not quite fitting together, and a difficult challenge to pull the threads together. Introducing a Multiversal threat, and using that threat to merge the realities, would be a smart move. What's more, a TV adaptation of Crisis on Infinite Earths would be an exciting prospect for DC fans.
Could This Plot Be A "Crisis"?
Right now, Supergirl stands alone - separated from the rest of The CW's superhero shows. Any characters who debut in Supergirl (such as Tyler Hoechlin's Superman) will really only have a major impact on her series, and will largely be unable to interact with Arrow, The Flash, and Legends of Tomorrow. With rumors building that the Bat-family is soon to be added to Supergirl, that could become a very real problem.
I'd previously expected The Flash's "Flashpoint" arc to possibly merge the realities, but running a "Crisis on Infinite Earths" plotline through Supergirl might be another way to achieve the same. What's more, this would move Supergirl to the forefront of The CW's superhero shows. The growing background cast of Supergirl strongly suggests that The CW intends to make her their central character, so it would be sensible to have her play a major role in unifying the timelines.
If I'm right, it's entirely possible that the threat will be either the Anti-Monitor or Brainiac, and that the result will be a merging of the two timelines. The first crossover between Supergirl and The Flash was simply adored by fans, in part because of the superb chemistry between Melissa Benoist and Grant Gustin's Flash. Bringing the shows into the same reality would be a smart move, opening up unlimited crossover potential - especially with the likes of Superman and the Bat-family soon to crop up on Supergirl's world!
It's an exciting possibility, and if The CW heads down this direction, fans are sure to love it. Personally, I think it's inevitable, and this teased Supergirl-centric plot sounds like the perfect mechanic to make it work!
Do you want Supergirl to merge with The CW's other superhero reality? Let me know in the comments!