In the annals of pop culture history, fans will always revere David Fincher's Fight Club. It became famous for the big twist where Ed Norton's Narrator didn't realize he had dissociative identity disorder. All this time, his dark alter, Brad Pitt's Tyler Durden, was assembling a cult via their fight club to commit terrorist acts and raze a capitalist society.

Many other movies, such as Netflix's Sweet Girl, and even Marvel's Moon Knight, have tried to use this same angle regarding dissociative identity disorder with its protagonists. In the 2025 Sundance Film Festival, one emphatic mystery thriller, The Things You Kill, actually reworks this concept in a more disturbing manner.

The Things You Kill is from Iranian filmmaker, Alireza Khatami. It actually won the Directing Award in the World Cinema Dramatic category. . Unfortunately, Ali's life is in disarray. He's deemed infertile after medical tests, which heaps pressure on Ali, who struggles to tell his wife, Hazar, about why they can't have a child. He feels like it diminishes his adulthood.

. He even learns Hamit has a secret lover, which riles him up about how his mother was mistreated. In time, the gardener who randomly shows up on his plantation and asks for work becomes a key figure. This stranger, Reza, helps him murder Hamit in revenge. .

. Hamit was very violent with him, and as the investigation occurs, Ali found out he was with his mother, too. Thus, Ali has that energy of characters like Jon Bernthal's Frank Castle where he wants to punish and dispense his own brand of justice as judge, jury and executioner.

Reza, however, is the one who gets most aggressive when he knocks Hamit dead and buries him out in the desert. It plays on how Ali has been around men he thinks are alphas: subservient and scared. .

The film throws viewers a curveball. . All this time, Ali had two personalities, with Reza secretly plotting the kill. Once the murder is complete, Reza's form (older and angrier) is seen in reality operating as Ali. It explains why he and Hazar couldn't have kids, and why the younger-looking Ali kept harping on their age gap. Once Hazar and Ali's martial woes reach fever pitch, she leaves, letting Reza live and breathe more.

Reza begins trying to bribe officials for more water to the estate, confirming he believes he is the man Ali ought to be. It's even implied he has an affair with a younger student as he takes control. As this seedy behavior occurs, Reza's own sister suspects him of being shady when Hamit goes missing. . He wants to sell it so he can have treatment, reconcile with Hazar and have a child.

A massive turning point comes when he learns from his aunt how Hamit was abused by his father. It touches on generational trauma. . Hamit hid the truth because he didn't want his children hating their grandparents. It's not forgivable, but at least viewers understand why he couldn't internalize his own agony properly. He became controlling and vindictive; the very thing he hated as he repressed his past. The more he misses Hamit, the more he realizes he is killing off legacy, dynasty and the theme of family.

Once Reza absorbs all this, Ali returns to take over the body. It hints he has forgiven Hamit and understood the man couldn't cope with a sick wife. He and Hazar embark on a second chance, too. . In the end, his guilt remains. Additionally, hints for Reza's origin were dropped that Ali lived a sordid second life in America and that he had skeletons in his own closet. Reza may well have been that macho person he had to be as a migrant in America.

Ultimately, his own lies and the fact that he condemned Hamit, all while being a hypocrite, means he won't ever be able to kill off that dark part of himself. In Fight Club, the Narrator and Tyler had a greater purpose. They were a cure for each other and society, leaving the selfless Narrator embracing the chaos and change he instigated. But in Ali's case, the selfish Reza is nothing more than a curse in a personal story about how vengeance consumes on the most granular level, while bringing out evil that may have been residing inside before. In that sense, Reza and others like him will always be venomous to their own, and civilization, in general, as they kill off their morals and ethics for self-gain.

The Things You Kill was screened at the 2025 Sundance Film Festival.