If you’ve seen Spider-Man: Brand New Day, then you now know all of those rumors and reports were correct.
Stranger Things star Sadie Sink is indeed the MCU’s Jean Grey. But Brand New Day introduced an element of Jean’s past from the comics that the Fox live-action X-Men films never touched on, Jean’s older sister, Sara Grey. In the film, what became of Sara led to Jean’s turn to the dark side, so to speak, and a foundational moment for her character arc. But Sara Grey as a character has a history in the pages of Marvel Comics, going back to Uncanny X-Men #136, a key issue in Chris Claremont’s Dark Phoenix Saga.
The First Mentions of Sara Grey in Uncanny X-Men
Jean Grey having an older sister first gets a mention in 1966’s X-Men #22. Jean describes visiting “a sister in Albany.” Eventually, Chris Claremont introduced Jean’s elder sister, now named Sara, when a Dark Phoenix-controlled Jean, during a moment of clarity, went to her family home. Sara (originally spelled Sarah) was present at the Grey residence, and it was only then that she learned Jean was even a mutant. Jean read her mind and learned that she worried that her two kids would also turn out to be mutants. Jean died in the very next issue, Uncanny X-Men #137 from 1980.
In a story one year later in Bizarre Adventures, we learned how Sara actually knew her sister was a mutant hero, but after a dangerous encounter with Atlantean villain Attuma, Jean psychically erased knowledge of her mutant life from Sara’s mind. When Jean died, that psychic block dissipated, and Sara remembered everything again. Chris Claremont was clearly setting up Sara Grey for bigger things.
Sara Grey Almost Became a Founding Member of X-Factor
Sara almost had a superhero career herself. When Marvel launched X-Factor in 1985, it reunited the original five X-Men after 15 years. But at the time, Jean Grey was still very dead. Writer Chris Claremont had no desire to resurrect Jean, so he proposed that her sister Sara was indeed a mutant too, and should take her spot. In Claremont’s pitch, her power went undetected, as her mutant ability was to unlock the latent powers in other mutants. She would have effectively replaced her sister as the new Marvel Girl. But Marvel’s EIC Jim Shooter overruled Claremont, and Jean Grey came back to life.
The Disappearance and Death of Sara Grey
Subsequent issues of X-Factor mentioned that Sara Grey Bailey and her husband Paul became mutant rights advocates. After Jean returned from the dead, she learned her sister went missing in X-Factor #12. Bigots firebombed their home, but they were not present. The mystery of what became of Sara remained for almost a decade. Eventually, we learned that the anti-mutant billionaire Cameron Hodge’s followers killed Sara and her husband. However, the alien robotic race, the Phalanx, absorbed her body into their Borg-like collective. Later, her children were killed by the alien Shi’ar, who murdered the whole Grey bloodline, as a way of preventing another Dark Phoenix from rising.
Jean Grey as Phoenix Brings Her Sister Sara Back to Life
Very recently, however, Jean Grey as the Phoenix essentially willed her older sister back to life. (But not her family? That seems mean, Jean). This happened in 2025’s Phoenix #11. She now has the powers that Claremont originally intended for her, to detect and unlock the X-gene in others. Her presence after death made reality unstable, but Jean defended her sister against powerful cosmic entities like Eternity and the Living Tribunal. They allowed Sara to continue existing as the Beacon, a cosmic judge. So for now, Sara Grey continues on in the Marvel Universe, after being cast aside decades earlier.
Sara Grey in Spider-Man: Brand New Day
In Spider-Man: Brand New Day, Sara Grey and her sister Jean were teenage runaways. And both had psychic powers of considerable strength. In this version, both sisters did not have loving parents as they did in the comics. Sara (Olivia Booth-Ford) mentions her mother in particular not being kind and tossing them away. After living on their own, we see how the government agency Damage Control kidnapped Sara to experiment on, and use for its own ends. This leads Jean to go on a rampage to find her sister, who she believes is still in Damage Control custody.
Eventually, Jean finds out the sad truth. Sara died during one of Damage Control’s inhumane experiments, conducted by the agency’s head, William Metzger (Tramell Tillman). However, we never see a body, so who knows if Sara Grey has a future in the MCU or not. She could have used her considerable power to make Damage Control think she was dead. But we have a feeling if any of that plays out, it’ll be in the MCU’s X-Men films. We have a feeling that Sara’s death is substituting the death of Jean’s childhood best friend Annie in the comics. That childhood event trauma truly unlocked her Omega-level mutant powers. We’ll see if Olivia Ford Booth’s Sara Grey gets mentioned in the upcoming X-Men reboot, or maybe even appears.
Spider-Man: Brand New Day is currently playing in theaters everywhere.