While everyone is crowded around trying to figure out what’s going to happen in Avengers: Doomsday, recently sifting through AI-generated spy shots and promo photos, there’s one actually interesting mystery in the MCU right now. Who is Sadie Sink playing?
Back in March of this year, it was announced that Stranger Things star Sadie Sink would be starring alongside Tom Holland in the upcoming Spider-Man: Brand New Day, a quasi-reboot of his place in the MCU. But what has never been mentioned or confirmed or even leaked is who she is actually playing. Now, there’s a new report that Sadie Sink and her character are being added to Avengers: Secret Wars, the Avengers film that’s after Doomsday.
HOLLYWOOD, CALIFORNIA – NOVEMBER 06: Sadie Sink arrives at the Los Angeles Premiere Of Netflix’s “Stranger Things” Season 5 at TCL Chinese 6 Theatres on November 06, 2025 in Hollywood, California. (Photo by Steve Granitz/FilmMagic)
FilmMagic
Who has Sadie Sink been rumored to play? I mean, who hasn’t she? We have:
- The “real” version of MJ, Mary Jane, not Michelle Jones
- Gwen Stacy, a new Pete love interest (previously played by another famous redhead turned blonde, Emma Stone)
- Felicia Hardy, aka Black Cat
- Rachel Cole-Alves, a Punisher sidekick, with Punisher confirmed for Brand New Day
- Firestar, part of the Spider-Man and His Amazing Friends era.
- Jean Grey, a prominent, all-powerful member of the X-Men
- Mayday Parker, who would be Tobey Maguire Spidey’s daughter
- Spider-Woman, Jessica Drew, frequently in Spidey storylines in addition to her own.
The most recent update was Sink seen on set filming, still with her trademark red hair, possibly wearing camo and combat boots, which gave some validity to the idea of the Rachel Cole-Alves theory.
But now? If she is skipping Doomsday to go straight to Secret Wars, that probably rules out a large chunk of this list, and raises the likelihood of sometimes-X-Man Firestar, or the hugely important Jean Grey role. Though Jean Grey being a prominent figure in Brand New Day would certainly be way, way out there in terms of concept.
You can see what I mean here though in terms of just how big a mystery her character is. That’s at least eight different rumored parts for one actress, a huge range at that, and we’re still no closer to figuring out who she actually is. We don’t even know if Tom Holland is in Doomsday or Secret Wars yet, but Sink is already heading over? That’s certainly strange, to say the least.
Spider-Man: Brand New Day releases on July 31, 2026, ahead of the December 2026 release of Avengers: Doomsday. We are probably a little early for any sort of trailer at this point, but it’s possible that even when one does arrive, we still don’t know who Sink is playing, even if she appears in the trailer in some capacity. So the question is, why is Marvel keeping this so close to the vest if it’s not a really big deal?
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Source: https://www.forbes.com/sites/paultassi/2025/11/20/somehow-a-stranger-things-star-is-now-the-mcus-biggest-mystery-sadie-sink-spider-man/
