If you've avoided having Split spoiled for you this long you may want to go see it and fix that.
While most everybody who went to see M. Night Shyamalan's Split was probably expecting a twist of some kind, it's unlikely they were expecting the one that they got. Since then, everybody has been trying to figure out how Split fits into a larger universe. Now, the director has spoken out about some of the early ideas that he's having regarding how Split and Unbreakable might come together in an eventual third movie.
My thought bubble would be---again, don't hold me to this---but Elijah never got out of the institution. He was just a guy who believed this. But David doesn't quite 100 percent believe it that way. He just thinks that he is particularly meant to do this, and [that belief] is kind of faded a little bit. Like, this idea of comic books, that Elijah was saying the comic book world is based on reality, that it's real---there's no other evidence for this. It's this crazy guy who has this bone disorder who's in an insane asylum. But then [Split] comes up, and he's like, 'Oh my God, he's right.'
Speaking on MTV's Happy Sad Confused Podcast director M. Night. Shyamalan was asked about what we might see in a follow-up movie and, while it's clear from the way Shyamalan phrases the setup, that nothing has yet been set in stone, it's clear that he has an idea of how the events of Split would impact Bruce Willis' character of David Dunn.
Essentially, it would seem that David Dunn hasn't necessarily been out playing superhero and saving the world since the end of Unbreakable, at least not from the super villain types of characters that Mr. Glass represented. Dunn hasn't come across other people like Glass and thus has started to believe that they don't really exist. Until he's sitting in a diner and learns on the news about somebody who is capable of physically transforming into a monster. This was a moment of clarity for David Dunn, and it could potentially launch the events of whatever movie comes next.
It's really only a starting point for a future movie, which Shyamalan has openly said that he plans to make, but it's not a bad place to start. It explains where Bruce Willis' character has been for the last two decades and gives us an idea of what that moment at the end of Split really meant for him.
Audiences were more than a little shocked when it turned out that Split was taking place inside the same worlds as M. Night Shyamalan's 2000 hit Unbreakable. It was a twist on the director's traditional film twist, in that it wasn't necessary for the story, but it still causes one to look at the entire film in a different way afterward.
Split seems to have won M. Night Shyamalan many of his fans back and we're certainly intrigued to see where this story goes from here. Hopefully, we won't have to wait too long to find out, although it's possible we won't even know we're watching it until the credits roll.