The following contains major spoilers for Doctor Strange in the Multiverse of Madness, now in theaters.
The Marvel Cinematic Universe has more or less reached the halfway point of Phase Four, with five of its announced ten-movie slate already in theaters and a similar split for the attendant Disney+ series. The franchise has kept fans guessing about where it might go, though a few clues have presented themselves. Presumably, there are plans for a colossal Avengers-style crossover, sometime after the release of The Marvels in July, 2023 and doubtless entailing the formal arrival of the Fantastic Four in the MCU.
But that still leaves a lot of potential directions for the franchise, and Phase Four has already used several threats that could serve as a cosmos-shattering danger to bring a disparate group of heroes together in the final chapter. While there’s still time for a new figure to arise -- villains in the finales of previous Phases, such as Loki and Ultron, were comparative latecomers -- there are already more than enough potential dangers to make for a suitably epic conclusion to the latest chapter. So, let's look at a list of those potential threats that have appeared thus far in Phase Four.
The Scarlet Witch Can Bring the MCU to Its Knees
The Scarlet Witch is major player in Phase Four, with her having her own series and a prominent role in the Doctor Strange sequel. The danger she represented grew exponentially during that time, to the point where it potentially threatened all of creation. Her status following the events of Doctor Strange in the Multiverse of Madness is unknown, but with at least one Wanda variant confirmed to survive and countless more out there as replacements, bringing her back maybe easier than it appears. Bringing her back could also introduce cosmic threats such as Chthon and Mephisto, and with stories like "House of M" still lingering, Wanda may be the perfect catalyst to bring Phase Four to a finish.
Incursions and Variants Provide a New Kind of Enemy
The creation of the multiverse has been the signature development of Phase Four, triggered by Loki’s paradox-incurring escape following the Battle of New York in Avengers: Endgame. That led to the discovery of the Time Variance Authority, variants such as Sylvie and the murder of He Who Remains to unleash an infinite wave of new realities into the MCU. That created colossal threats in both Spider-Man: No Way Home and The Multiverse of Madness. And further incursions could lead not only to a variant villain but could also facilitate an adaptation of a comic storyline like Secret Wars.
Kang the Conqueror May Mess With the MCU's Timeline
Loki also provided a much more specific villain to serve as the Big Bad for this part of the MCU’s timeline. Kang the Conqueror -- a variant of Nathaniel Richards -- ended the first season of Loki seemingly in charge of the TVA. And with He Who Remains warning of “worse” versions of himself, he’s the most likely candidate currently in the MCU to serve as a crossover-worthy foe. Kang has deep roots with both the Fantastic Four and Avengers, giving the creators plenty of in-comics storylines to work with.
The Celestials Want the Fight Back in Space
The MCU got treated to the unexpected appearance of a Celestial at the conclusion of Eternals. And the movie ended with every member of the titular team off Earth, either seeking to warn other planets about the Celestials or facing the music with Arishem. That gives them a tie-in to some of the MCU’s more far-flung characters -- particularly the Guardians of the Galaxy, whose third film will be one of the lead-ups to the Phase Four finale. If the MCU decides to bring them together, it could use another Celestial as the threat, or even a similar non-Celestial figure such as Galactus, which would justify not only a massive hero team-up but also facilitate the arrival of the Fantastic Four.
The Skrulls Can Be Everywhere at Once
Marvel’s shapeshifting aliens played a huge role in Captain Marvel and will presumably resurface in the upcoming Secret Invasion series. But several questions remain unanswered, and the events of Secret Invasion could readily lead to a far more cosmic threat. The benevolent Skrull led by Talos may be a political minority among their people, so the arrival of a far less benevolent faction could readily springboard from Secret Invasion to a much larger conflict.
