Sadie Sink’s Secretive Marvel Role Fuels Fan Theories

Sadie Sink is set to make her Marvel Cinematic Universe debut in Spider-Man: Brand New Day, appearing alongside Tom Holland. While her involvement has been confirmed, Marvel is keeping tight-lipped about the character she’ll be playing. This secrecy has sparked a wave of curiosity, with fans and punters alike speculating about her potential role and what it might mean for the wider franchise.

Rumours and Speculation Around Sink’s Character

Recent chatter suggests Sink could be lined up for a part in Avengers: Secret Wars after her appearance in Brand New Day. However, there’s been no official word on whether her character will actually cross over into that much-hyped event. The lack of details has only added fuel to the fire, with many wondering if her role is a one-off or the start of something bigger.

Here’s more information on Avengers: Secret Wars:

Movie: Avengers: Secret Wars
Directors: The Russo Brothers
Release Date: December 17, 2027
Major Cast: Joseph Quinn, Vanessa Kirby, Pedro Pascal, Robert Downey Jr.

With so little to go on, most of the talk about Sink’s character is pure guesswork. Still, the buzz around her casting hints that Marvel might have bigger plans for her down the track.

Possible Paths for Sink in the MCU

Even if you put aside the Secret Wars theories, there are a few other ways Sink’s role could play out. Marvel’s keeping the details close to their chest, so it’s anyone’s guess at this stage. One idea is that her character is meant to stick around the Spider-Man side of things, at least for now. Another theory is that she could be an original creation, not pulled from the comics at all.

Marvel has a habit of introducing new faces to keep their options open, especially as the Multiverse Saga unfolds. If that’s what’s happening here, Sink’s part might start off small, with the chance to grow if the story calls for it. Fans have tried to piece things together by looking at the characters she’s rumoured to play. As Forbes pointed out, there’s been a lot of talk about Jean Grey, mainly because of Sink’s age, profile, and the timing of her arrival as Marvel edges closer to the Mutant Saga.

With no confirmation about who she’s playing or how long she’ll stick around, Marvel’s left the door wide open. It’s possible that Brand New Day is just the beginning for Sink in the MCU.

How Marvel’s New Approach Shapes Character Introductions

The Marvel universe is in a different spot these days compared to its early years, and that’s changed how new characters are brought in. Lately, Marvel’s been happy to introduce new faces without spelling out how important they’ll be straight away. Characters like Shang-Chi, Yelena Belova, and America Chavez all started out in their own stories before being set up for bigger things. Sometimes, especially with those introduced in Disney+ series, Marvel takes its time before bringing them back.

This more relaxed approach fits with the current Multiverse Saga, where the studio’s still working out how everything fits together. New characters can pop up in one film without their whole future being mapped out from the start. In that light, Sink’s arrival in Brand New Day matches how Marvel’s been doing things lately—introducing someone first, then letting their place in the bigger picture develop over time.

Spider-Man: Brand New Day is due for a global cinema release on 31 July 2026.