The second instalment, Split, was released in 2016, and the final one, Glass, currently showing here, has the protagonists of each film woven into the storyline.
It topped the North American box office with US$47 million (S$64 million), with Bruce Willis and Samuel L. Jackson returning as David Dunn and Elijah Price/Mr Glass respectively from Unbreakable.
And from Split, James McAvoy reprises his role as Kevin Wendell Crumb alongside the Horde of multiple personalities that live inside him, including the serial killer supervillain Beast.
The invulnerable superhero Dunn pursues the Beast, and brittle-boned evil genius Price orchestrates the action.
Though Unbreakable got positive reviews upon its release and won a cult following over time, Shyamalan admitted the initial naysayers did get to him.
The 48-year-US film-maker said at our interview at the Crosby Street Hotel in New York City: “For about 14 years, I wasn’t planning on making (the trilogy) and finishing it.
“There was such a weird reception to Unbreakable. I think it was hurtful.
“It was a weird reaction even with audiences, this sense of not knowing what I was trying to do. ‘You were trying to do a serious comic book movie?’
“I just wasn’t emotionally willing to go there again.”
Unbreakable came out before the popularity of Marvel-DC comic book superhero blockbusters over the last decade, and Shyamalan had moved on to other films, but the question he heard over and over was when he was making the sequel.
He said: “In my head, I was searching for those ideas that had lent themselves to a sequel, and Split was the classic example of that.
“So I kind of tricked my way back into the trilogy by making the second one without really telling anybody it was a sequel.”
Then he looked at all the outlines he had from 1999 and planned Glass.
“Unbreakable was supposed to feel like David, and Split was supposed to feel like Kevin Wendell Crumb – violent, weird and inappropriately funny. Then Glass is supposed to feel like Elijah, like a majestic chess match going on in the movie, so I kind of always had that in my head.”
Where Shyamalan breaks from the norm is presenting his superpowered heroes like real human beings.
He explained: “What are the things in the real world that we don’t know about that are naturally extraordinary?
“Like, there is a bone disorder that makes you so fragile your bones break, so wouldn’t that mean the opposite of that exists somewhere? Someone whose bones are really dense?”
Dissociative identity disorder, the condition that Kevin has, was another subject that interested him.
He continued: “How extraordinary, as a natural phenomenon that happens in the psychological world from this intense trauma children go through, that their brains learn to do this extraordinary thing we can’t do in a normal upbringing.”
When asked about his own superpower, he said: “I genuinely believe in other people’s superpowers, whether that is an actor or a child or anybody that I meet in my philanthropy.
“I genuinely get pissed when someone is taught that they don’t have agency, that they are not extraordinary. I believe that about all of us, and I want that for all of us.”
Shyamalan then related the story of how he met the “miracle” McAvoy in San Diego at a comic convention and knew he was the one for Split.
He recalled: “I wrote a part that I am not sure anybody could have played.
“Who could play a child, could play the physicality of the Beast, could crawl on a wall, could play a woman?
“Then I had the one guy who could play this walk up to me at Comic-Con. He started talking to me and I was like, as he was talking to me, ‘This is the guy!’
“What I was seeing in him was gentleness, the everyman, empathy. I was like, ‘Wow, what if a really sweet regular guy played this role? What would that be like?’ He would bring an accessibility to it.
“What I didn’t know from his body of work prior to that is he is an amazing entertainer. He thinks the thought and his body responds. What a perfect role for someone who is kind of an intuitive physical genius.
“And also, how many people can do that many accents? I didn’t even know he was Scottish for the longest time. I thought he was British,” he said with a laugh.
Shyamalan believes the Unbreakable-Split-Glass story could have more sequels, but he is not going to do it.
He said: “That is not the way I am built. The idea of returning to an emotion that existed for the last two years feels weird for me.
“No one asks me to tell these stories. I am not hired to tell these stories. I tell these stories and say, ‘Hey, will you pay for it, will you distribute it?'”
The writer is the president of the Hollywood Foreign Press Association, a non-profit organisation of entertainment journalists that also organises the annual Golden Globe Awards.
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