Split was advertised as yet another one of M. Night Shyamalan's standalone movies, but the big twist (as we've come to expect from the writer/director) at the end of that movie was that it existed in the same world as Unbreakable. But when he was preparing for Split, it went over James McAvoy didn't catch on that the horror thriller was meant to connect to Shyamalan's 2000 superhero movie. As McAvoy recalled:
I read the first version of Split that I got sent and there was a little tenuous clue there -- if I had been sharper eyed, I'd have seen it, but I missed it. I got into rehearsals and he kept talking about Unbreakable.
Going off this comment, it sounds like it initially wasn't as obvious in Split that the movie was tied to Unbreakable, hence why this little clue James McAvoy mentioned went over his head. However, as M. Night Shyamalan kept referring to Unbreakable and its main characters, David Dunn and Elijah Price, eventually McAvoy finally realized what was happening, though it took longer for him to admit to Shyamalan that he'd been oblivious about what was happening. Continuing in his interview with Digital Spy, McAvoy said:
And then it became clear, it dawned on me, the veil was lifted and I was like, 'Oh my God'. Then a few weeks after that, I came clean with him and I was like, 'Dude, I did not get that at all' I think he realized that the little clue he was giving everybody just needed to be amped up and he ended up coming up with a really cool scene at the end as well.
I'm curious about what this "little clue" was since in Split's main story, it's not obvious that Kevin Wendell Crumb, a.k.a. The Horde, lives in the Unbreakable world. Sure his 24th and most dangerous personality, The Beast, is capable of physical feats no ordinary human can do, but that can just be attributed to the usual science-defying weirdness that you find in a lot of horror movies.
Thankfully, Split's last scene made the connection perfectly clear, as Bruce Willis' David Dunn was in a diner as a new report about Kevin Wendell Crumb played, and he name-dropped Mr. Glass when a fellow patron noted a similarity between this case and what the wheelchair-bound criminal had done nearly two decades earlier. You can re-watch that moment below.
With Unbreakable and Split now tied together, the path was clear for a movie bringing the main characters from both movies together, a.k.a. Glass. The final chapter of the Eastrail 177 trailer sees David Dunn, Elijah Price and Kevin Wendell Crumb being held in the same high security hospital, and when Elijah and Kevin join forces and conspire to escape, it'll be up to David, a.k.a. The Overseer to stop them before a lot of people die. For those of you who particularly enjoyed Split, James McAvoy stepped it up a lot for Glass by getting way more jacked and playing 20 different personalities, meaning that all of Kevin's other selves will finally be accounted for.
Glass opens in theaters this Friday, January 18, but you can read CinemaBlend's review of the movie now.