In Season 1, Mr. Robot revealed that its titular hacker (played by Christian Slater) was not, in fact, a venerated cyber prophet, but a construct within the mind of main character Elliot Alderson. Now, in its final season, the show has teed up the bombshell that Mr. Robot isn't Elliot's only other personality: in Oct. 13's "Payment Required," Elliot's mother implied, via a flashback, that her son has a third identity, so far unknown to the audience. This has understandably led to a number of fan theories about who "the other one" Elliot's mother referred to could be — though series creator Sam Esmail told The Hollywood Reporter this is one twist no one has predicted.
Still, that doesn't mean it's impossible to figure out. Esmail also said "the other one" has been in place since the very beginning of the series, which means there should be plenty of evidence to be gleaned from previous episodes — Esmail even confirmed so. "You guys could technically figure it out because it's been in the show the whole time," he told THR. And boy, are fans trying to. Here are the best theories based on the (very little) we know so far.
It's Another Elliot
Along the lines of the previous theory, Redditor Grooviest_Saccharose believes the third identity is not only leading the operation but would take the appearance of Malek. In a separate theory, user j4yne also suggested Malek has been playing both the Elliot and "the other one" personalities throughout the show without the audience realizing. Another possibility is that the person will be Elliot (the real Elliot), but be portrayed by a different actor. After all, fans have noticed how two different actors have played young Elliot — Aidan Liebman and Evan Whitten.
It's Another Mr. Robot
Instead of two Elliots, CascadeThrowAway35 wondered on Reddit if two of the three personalities are Mr. Robot. One is the more compassionate Mr. Robot, who acts similar to Elliot's father. The other is one who has more rage. Heeyoonchung noted that sometimes Slater's Mr. Robot wears a hat and glasses while sometimes he doesn't, so this could be a clue that he takes up two parts of Elliot.
"The other one" revelation occurred in the same E Corp boardroom where Elliot met Tyrell at the end of the pilot episode. Reddit user an27725 pointed this out, leading to a discussion about if Tyrell could be the other identity. Many people contested that Tyrell has been firmly established his own person, so senior_chief offered that perhaps instead, the third personality is the one who works most closely with Tyrell.
Elliot's mom gave the third personality a male pronoun, but Magda isn't really one to be trusted. So could Elliot's other ego be a woman — and could it be another family member? Mr. Robot is personified by Elliot's father Edward, so it's not out of the question to wonder if Elliot's sister Darlene is "the other one," especially since Darlene often reminds Elliot about things from his past and present. For example, when Elliot misremembered how he fell out of the window in the Season 3 finale, she told him, "I'm here to remember for you." She's also the person who made Elliot and Mr. Robot realize there's a third identity when she informed Elliot that she'd already told him about Vera. Maybe in the end, Darlene didn't need to tell her brother about Vera because she has been part of Elliot and Mr. Robot all along — whether she's been in the driver's seat or the backseat.
They Are Hiding Behind The F-Society Mask
While this doesn't necessarily help identify who "the other one" is, one Reddit theory that has picked up steam is that the other personality has been onscreen hiding behind the fsociety mask. The mask comes from the fictional movie The Careful Massacre of the Bourgeoisie, which holds meaning for Elliot and Darlene. But if the third alter ego is behind the mask, it makes him even more significant to the storyline.
Other popular theories are that "the other one" could be Angela, creator Esmail, or even the audience themselves (after all, Elliot is often addressing his "friend"). As the series finale draws closer, keep an eye on new theories to see if someone is able to crack Esmail's elaborate final Mr. Robot puzzle.