Split is a 2016 American psychological horror film written, co-produced and directed by M. Night Shyamalan and starring James McAvoy, Anya Taylor-Joy, and Betty Buckley. The film follows a man with 23 different personalities who kidnaps and imprisons three teenage girls in an isolated underground facility.
Casey is a withdrawn teenager, having been molested as a child by her uncle John, her legal guardian since her father died from a heart attack. She and her classmates, Claire and Marcia, are kidnapped by Kevin Wendell Crumb, a man suffering from dissociative identity disorder (DID). Kevin, who is in therapy with Dr. Karen Fletcher, has 23 distinct personalities that Dr. Fletcher has identified within Kevin. In his mind, these personalities sit in chairs in a room, waiting for "Barry", the dominant personality, to grant them their turn "in the light" (in control). She has also found that Kevin's physiology changes with each personality. Recently, "Barry" has refused to allow "Dennis" or "Patricia" their turns, in part due to Dennis' tendencies towards bothering underage girls and Patricia's undesirable traits, and also because both appear to worship "The Beast", a yet-unseen 24th personality. Fletcher has found that she can bring back Kevin's own personality by speaking his full name.
Kevin locks the girls in a cell in his underground quarters. They recognize his DID, and Claire attempts to use this to escape but is caught by "Dennis" and separated from the others. Kevin continues going to work and attending appointments with Fletcher. Fletcher soon recognizes that "Dennis" has displaced "Barry" as the dominant personality. It's revealed that when Kevin was a child, his father left on a train one day and never returned. As he grew up, Kevin was abused and terrorized by his mother, who suffered from obsessive–compulsive disorder (OCD). He later experienced an awkward incident with two teenage girls where they forced Kevin to touch their breasts, which Fletcher believes has triggered "Dennis" to take over and that he may have abducted the three missing girls.
Marcia attempts to escape but is caught by "Patricia". Casey befriends "Hedwig", a young boy. She convinces "Hedwig" to let her out of her cell to see his bedroom, believing that there might be a means of escape through the window "Hedwig" has described in that room, but she finds that it is only a drawing of a window. She takes a walkie-talkie from Hedwig and uses it to call for help, but the man at the other end thinks it is a prank. "Patricia" takes over and subdues Casey. Fletcher visits Kevin's home, where he reveals that he has met "The Beast". Fletcher feigns going to the bathroom, searches the house, and finds Claire. "Dennis" suddenly appears, sedates Fletcher and locks her up.
While Kevin runs an errand, "The Beast" takes over, giving Kevin superhuman abilities. Fletcher writes Kevin's full name on a piece of paper before "The Beast" arrives and kills her. Casey escapes from her cell, only to find that "The Beast" has already devoured Marcia and watches in horror as he devours Claire too. Casey finds Fletcher's body and the piece of paper. "The Beast" approaches her, but she calls out Kevin's full name, bringing Kevin forth. Upon learning of the situation and realizing that he has not been in control for two years, a horrified Kevin begs Casey to kill him with a shotgun he has hidden. This prompts all 24 personalities to fight for control of "the light", but "The Beast" takes hold again. Casey retrieves the gun and ammunition before escaping into an underground tunnel, where she shoots "The Beast" twice to no effect. She locks herself in a caged area whose bars "The Beast" begins to pull apart. Then he sees faded scars across her body, a sign of her abuse. Having previously declared his plans to rid the world of the "impure" and "untouched"—those who have never suffered—he considers Casey to be "pure" so he spares her and he runs off.
Casey is rescued and learns that she was being held at the Philadelphia Zoo, where Kevin had been an employee. When Casey is asked if she is ready to return home with her uncle, she hesitates to answer. In another hideout, "Dennis," "Patricia," and "Hedwig" discuss the power of "The Beast" and their plans to change the world.
In a diner, several patrons watch the television as a news correspondent reports that Kevin's numerous personalities have earned him the nickname, "The Horde." A patron notes the similarity to the case of a wheelchair-bound criminal incarcerated 15 years earlier who was also given a nickname. As she tries to remember the nickname, the patron sitting next to her, David Dunn, says it was "Mr. Glass."
- James McAvoy as Kevin Wendell Crumb / The Horde: a sufferer of dissociative identity disorder (DID), who has 23 prominent personalities, each with something peculiar or dangerous for his captives. Kevin's body chemistry changes with each personality, resulting in his 24th and final personality, "The Beast": a grotesque and cannibalistic sociopath with superhuman capabilities, such as inhuman bodily strength, enhanced speed and agility, along with near-invulnerability and unnatural mobility which imbued him with the ability to scale walls, but resulted in his insatiable hunger for raw human flesh.
- Anya Taylor-Joy as Casey Cooke, a young girl with a traumatic past and a history of self-harm, who is kidnapped by "Dennis", one of Kevin's personalities, to be sacrificed to the Beast.
- Izzie Coffey as 5-year-old Casey
- Betty Buckley as Dr. Karen Fletcher, a psychologist who attempts to help Kevin with his DID, and believes that DID can, in extreme cases, cause physiological changes.
- Haley Lu Richardson as Claire Benoit, Mr. Benoit's daughter, a classmate of Casey and a friend of Marcia, who is also kidnapped by "Dennis" to be sacrificed to the Beast.
- Jessica Sula as Marcia, a classmate of Casey and a friend of Claire, who is also kidnapped by "Dennis" to be sacrificed to the Beast.
- Brad William Henke as John, Casey's paternal uncle.
- Sebastian Arcelus as Mr. Cooke, Casey's father.
- Neal Huff as Mr. Benoit, Claire's father.
- Kim Director as Hannah
- Lyne Renée as Academic Moderator
- M. Night Shyamalan as Jai, a security guard in Dr. Fletcher's apartment building.
- Rosemary Howard as Mrs. Crumb, Kevin's mother.
- Bruce Willis as David Dunn (uncredited cameo)
Shyamalan conceived the idea for Split years before he actually wrote the screenplay. He explained, "In this case I had written the character a while ago, and I had written out a few scenes of it, so I even had dialogue written out, which is really unusual for me. It sat there for a long time, and I really don't have a clear reason why I didn't pull the trigger earlier. But this felt like the perfect time to do it, with the type of movies I'm doing now, and the type of tones I am interested in – humor and suspense."
On October 2, 2015, James McAvoy was cast in the film to play the lead, replacing Joaquin Phoenix. On October 12, 2015, Anya Taylor-Joy, Betty Buckley, Jessica Sula, and Haley Lu Richardson were added to the cast. On October 27, 2015, Universal Pictures came on board to release the film and titled it as Split.
The character of Kevin had been in one of the early drafts of Shyamalan's Unbreakable, but he had pulled the character out, stating there were balancing issues at that time. With Split, he brought in some of the scenes he had written for Unbreakable around Kevin. The film ends with the appearance of Bruce Willis's character, David Dunn, from Unbreakable, who makes a comment in reference to the previous film, placing Unbreakable and Split within the same narrative universe. Shyamalan requested permission to incorporate the character from Walt Disney Studios, which had produced Unbreakable. Shyamalan met with Sean Bailey about the use of the character; they came to a gentlemen's agreement where Bailey agreed to allow the use of the character in the film without a fee and Shyamalan promised that Disney would be involved in a sequel, if developed. Shyamalan was very secretive of Willis' involvement in Split, removing the final scene from the film for test audiences.
Principal photography on the film began on November 11, 2015, in Philadelphia, Pennsylvania. Reshoots occurred in June 2016. During post-production, Sterling K. Brown's role as Shaw, Dr. Fletcher's neighbor, was cut from the film, as Shyamalan felt that his scenes were ultimately unnecessary. McAvoy broke his hand in a scene where he was supposed to punch a metal door, but missed the soft section of the door he intended to hit.