Spider-Man: Brand New Day took a different approach than its predecessors. The Wall-Crawler's first three MCU films painted very clear pictures ahead of their releases, revealing their villains and major story beats in marketing. Brand New Day kept its cards close to the vest, as Marvel Studios wanted to wait until the last second to reveal the identity of Sadie Sink's mystery character, a move it's used in the past to great success.
Theories ran rampant online leading up to Brand New Day's July 2026 release, ranging from Spider-Man's latest adversary being Typhoid Mary to Mayday Parker, Peter Parker's daughter from an alternate universe. The most logical explanation won out, though, as Sink brought none other than Jean Grey to life.
The X-Men are set to be a major part of the MCU's future. In fact, once the Multiverse Saga wraps up, Marvel Studios will kick off the Mutant Saga, which, as its name suggests, will hand over the spotlight to Cyclops and Co. Sink is already confirmed as a member of the cast of Jake Schreier's X-Men movie. And that might make all the smoke and mirrors around her character's introduction seem silly. However, there's a method to Marvel Studios' madness.
For starters, a good mystery always gets more butts in seats. Marvel fans who weren't checking X and subreddits for spoilers probably wanted to visit the theater to find out more about Brand New Day's villain and were pleasantly surprised to learn it was an important mutant.
There's also the risk factor to consider. Jean isn't typically depicted in a negative light, so Kevin Feige and Co. were going out on a limb by introducing her as an antagonist.
In the end, it all worked out. Jean had a memorable debut, going from an unhinged monster to a hero willing to help save the life of someone she barely knew. She also got to be part of a movie that became one of the highest-grossing of all time, shedding much of the baggage that followed her from Fox's franchise.
It shouldn't be all that surprising that Marvel Studios pushed all the right buttons when it came to bringing Jean into the fold. After all, hiding a major character introduction has become commonplace for the company. The only certainty now, when the Marvel Studios logo shows up, is that everything is not what it seems.
Major Character Introductions Where Marvel Studios Withheld the Truth
Mar-Vell
Carol Danvers joined the MCU at an interesting time. Her debut movie, Captain Marvel, came out right after Avengers: Infinity War and established the titular hero's relationship with Nick Fury, which began in the 1990s. It turned out that Carol was a member of the US Air Force who had an accident and landed on the Kree's doorstep.
Captain Marvel's marketing made it seem like Annette Bening was playing the Kree leader, the Supreme Intelligence. And while she technically did, the Supreme Intelligence took the form of someone Carol knew: Mar-Vell, a legend in Marvel Comics. Many fans theorized that Jude Law, who got cast as Yon-Rogg, another Kree warrior, was actually Mar-Vell in disguise. But Bening got the nod instead, even if it was only for a couple of scenes.
Agatha Harkness
Marvel Studios came out of the gate swinging on Disney+ with WandaVision, a mind-bending series that wanted to keep everyone guessing. Each week, the show jumped to another decade and changed its style. The only constant was the cast, including Kathryn Hahn as Wanda Maximoff's nosy neighbor, Agnes.
While fans had their eyes on Agnes throughout WandaVision's first few episodes, it was difficult to give her too much attention because of all the twists and turns. She flew under the radar long enough to strike, revealing herself as the powerful witch Agatha Harkness, who had been pulling the strings in Westview from the start. The Agatha reveal left the Mephisto truthers disappointed, but she played her part to perfection.
Billy Maximoff
Agatha took her oppurtunity and ran with it, leaving Marvel Studios with no choice but to give her a spinoff series. Agatha All Along focused on the titular witch's efforts to get her powers back after her run-in with the Scarlet Witch. But she couldn't complete her mission alone; she needed a coven.
At the start of the show, Agatha recruited a few magic users she knew from the past. She also took a strange teenager, who went by "Teen," under her wing. Agatha All Along's marketing didn't reveal Teen's identity. It took until the show's fifth episode to learn the truth: Teen was actually Billy Maximoff, Wanda's son, whom she created in Westview in WandaVision.
