Speculation surrounding Sadie Sink's role in Spider-Man: Brand New Day has intensified after multiple online insiders reiterated claims that she is set to play Jean Grey, one of the X-Men's most significant characters. While Marvel and Sony have not confirmed the casting, the renewed chatter has fuelled debate over what her role could signal for the studio's mutant plans. For fans, it has become one of the clearest recurring clues yet about how the X-Men may be introduced into the Marvel Cinematic Universe.