The Deceitful Stranger
Emerald Fennell's hit movie Saltburn has sparked dozens of theories, especially about who was really responsible for the deaths of the Catton family. While Ollie undoubtedly proves to be the primary deceitful stranger whose greed and lust for power becomes the Catton family's demise, there are many historical and allegorical lenses that could also place blame on other, more supernatural, factors.
Oliver stands at the gates of Saltburn with his suitcase in Saltburn.
At first, Ollie is an apparent outcast at the prestigious Oxford University who is driven by the appeal of exclusivity, power, and immense wealth. Ollie holds himself to a high regard that propels his deep sense of entitlement forward, first to have everything that 'cool guy' Felix has, and then eventually to become Felix as much as possible. This casts Ollie as a sociopathic killer who premeditated an entire plot to befriend and betray Felix, ruining his life within a matter of months. There is, however, the effect of the Saltburn estate itself which, much like Kubrick's Overlook Hotel in The Shining, might have a will of its own.
Oliver is wearing a robe and looks out at the mess on the estate grounds in Saltburn.
The Sinister Motivations
One theory pertaining to Ollie's sinister motivations in Saltburn points to the Saltburn estate itself and its requirement for blood sacrifices from its inhabitants. Much like the aforementioned theory about The Shining, the Saltburn estate, as this kind of monstrous Gothic entity, could have called for a changing of the guard, which is why Ollie met Felix and showed up to Saltburn when he did. In The Shining, Jack Nicholson's character Jack Torrence is being heavily influenced by the Overlook Hotel and its ghostly inhabitants to kill his family, which draws close parallels to Saltburn through this lens.
Oliver shirtless looking at the family's death stones at the end of Saltburn
In this regard, Ollie becomes a servant of the Saltburn estate, which can be seen as a metaphorical malevolent god or demonic force that essentially enlists Ollie to do its bidding. Ollie becomes an instrument of Saltburn's will, which is to clearly eliminate the Cattons from the residence. There could be many reasons why the Saltburn entity would want to get rid of the Catton family but the most logical reason would be that it sees them as unworthy and unappreciative of its magnificence. Ollie, whose obsession with Saltburn drives him to kill Felix, Venetia, and Elspeth, could have been supernaturally chosen by Saltburn as its desired heir.
Jacob Elordi as Felix half smiling in Saltburn
The Demanding Estate
Ollie essentially picked off each Catton family member one by one, except for Sir James Catton who appeared to have either died naturally or by suicide. Ollie, who is personally greedy and lustful of established wealth, takes the money and runs for the time being, knowing that there would be no immediate way of taking control of Salturn with James still around. Ollie waits for over fifteen years with the intention of returning to Saltburn and finally claiming sole ownership, manipulating Elspeth into signing it over to him in her will before killing her as the final sacrifice to the Saltburn entity.
Venetia deeply disturbed pouring wine into an overflowing glass in Saltburn
If the Saltburn estate actually does demand human sacrifices for its inhabitants to stay there, then Ollie would inevitably have to kill more and more people in order to maintain residency. This would support some of the symbolism referring to the Minotaur, who in Greek mythology was trapped in a Labyrinth and killed everyone who would enter. The Minotaur statue in the hedge maze on the Saltburn estate was actually made based on Ollie's figure, so it's quite possible that Ollie has metaphorically become a Minotaur trapped in Saltburn's Labyrinth who will keep killing in order to satisfy the sinister estate.
Rosamund Pike as Lady Elspeth Catton holds a cocktail and looks serious in Saltburn