The abuse that Kevin Wendell Crumb experiences as a kid in Split results in him developing Dissociative Identity Disorder and eventually, his superpowers. At the end of that movie, the Beast lets Casey, one of the teenagers he has kidnapped, go—all because she has suffered sexual abuse throughout her life.
It's only alluded to in the film, but it appears to be based on the animals in the zoo above where Kevin lives. In the third act, the Beast breaks out thanks to Dennis and kills two of the kidnapped girls, but allows protagonist Casey to live due to her own troubled past, recognizing a bond between them.
Her life was turned upside Down again after she was taken - alongside Claire Benoit and Marcia - by Kevin's 'Dennis' personality. She was held in an underground bunker of a zoo, until she was eventually found and rescued.
Barry has banned Dennis from “the light” because he's a known pedophile. Patricia was banned from the light, too. Because she and Dennis have certain “religious” beliefs that Barry (the dominant personality) feels are inappropriate and dangerous.
Kevin's mother failed to protect him from abuse and neglect, either due to her own damaged state or her lack of interest in fulfilling her role as a caregiver [1]. Her abusive behavior and neglectful actions contributed to Kevin's trauma and likely exacerbated his psychological struggles.
But Casey is different. Flashbacks interspersed throughout the action reveal that she was sexually abused by her uncle (Brad William Henke)—and that, after her parents' death, this uncle became her guardian. Casey's weirdness and introversion is traced to this abuse.
The film has been poorly received by mental illness and dissociative identity disorder campaigners. Mental health advocates warn that the film stigmatizes dissociative identity disorder and may directly affect those living with it.
John grooming Casey for sexual abuse. John Cooke is the secondary antagonist of the 2016 horror-thriller film Split, the second installment in the Eastrail 177 film trilogy. He is the sexually abusive uncle of protagonist Casey Cooke.
Producer and director M. Night Shyamalan and producers Marc Bienstock and Jason Blum's (2016) latest film, Split, is a horror thriller where the main character Kevin, played by James McAvoy, suffers from dissociative identity disorder (DID) and kidnaps three teenage girls.
Dr. Fletcher awakens long enough to write out Kevin's full name on a piece of paper before "The Beast" returns and kills her. "The Beast" then attacks and devours Claire and Marcia.
Kevin as "Dennis" knocked out Mr. Benoit and kidnapped three teenage girls, Casey Cooke, Claire Benoit, and Marcia, knocking them out with chloroform before taking them in an underground bunker of the Philadelphia Zoo, intending to use them as food for "The Beast".
Her father taught her how to hunt and how to shoot a gun. Casey was on a hunting trip with her father and her uncle John. During this trip, John molested her repeatedly. Shortly after, Casey's father died leaving John the only legal guardian to take care of her.
At the end of "Split," we find that the character with 24 split personalities played by James McAvoy lives in the same cinematic world as a character from another Shyamalan movie when Bruce Willis suddenly appears, playing David Dunn, the main character from 2000's "Unbreakable."
As for the actual final scene: it is a direct reference to Unbreakable, of course. As Willis' David Dunn sits at a counter, many remark at the television screen, wherein reporters breathlessly espouse that Kevin Wendell is now to be known as 'the Horde.
Each of the three protagonists of the Unbreakable trilogy (David Dunn, Elijah Price, and Kevin W. Crumb) have their own distinctive colors: David's color is green, Elijah's color is purple and Kevin's color is yellow. However, Kevin is a antagonist in Split, though he is briefly an antagonist and protagonist in Glass.
The Beast. The 24th and most dangerous personality to form. This personality changes Kevin's body chemistry and physiology to the point where his skin is impenetrable and can develop superhuman speed, strength, and durability. He is shown to be able to climb walls, bend metal bars, and survive shotgun wounds.
3) Your trauma is your superpower. This is the main theme of Split, and to be honest, it's a troubling one. It's voiced most clearly at the end, by a (literal) predator, who tells Casey that she is pure because of what she's endured at the hands of others.
The scene in question comes in the film's final act when we witness the Beast's first kill; the moment a modus operandi is established as he crushes Betty Buckley's Dr Fletcher to death using his 'anaconda' grip.
So the Beast does indeed emerge – McAvoy becomes ultra strong, his skin gets super hard, he gains the ability to climb impossible walls (somewhat unconvincingly) and his voice gets even creepier. And he does indeed completely eviscerate and eat two of the girls.
To avoid his mother's abuse, Kevin began to develop multiple personalities as a defense mechanism. Dennis, the protector alter with obsessive-compulsive cleaning habits, was a direct result of his trauma. Kevin ultimately developed 23 individual personalities, each of which are able to take control.
In Unbreakable, it was revealed that Elijah was responsible for the train crash as he was looking for his hero counterpart. Kevin's father, Clarence Wendell Crumb, was a passenger on the Eastrail 177 train, the same train David Dunn boarded one day and which derailed, killing all passengers except David.
Introduced in Split, Kevin Wendell Crumb's traumatic origins and the subsequent Dissociative Identity Disorder it caused set up his eventual transformation into the fearsome Beast.
Research indicates a strong correlation between childhood trauma, particularly physical and sexual abuse, and the development of DID. This connection is echoed in Kevin's backstory, which reveals a history of abuse and neglect, contributing to the fragmentation of his identity.
Night Shyamalan's Split drew inspiration from the real life court case of Billy Milligan. Milligan's landmark verdict of not guilty based on Dissociative Identity Disorder still captures public interest today. Shyamalan's portrayal of DID in Split is based on Milligan's case but takes many creative liberties.
