MCU Phase 6's MCU Phase 5 and 6's characters and storylines.
Technically, MCU Phases 1 to 3 saw several crossovers, like the Civil War and Infinity War storylines, which culminated in MCU Phase 3's Secret Invasion. Beginning in Secret Invasion, it seems Marvel will be changing the definition of a crossover and delivering new ones that exceed the expectations of long-time Marvel viewers. Like Thanos' snap, the Skrull invasion is bound to forever change whichever characters will be involved in the MCU's first announced crossover.
With Avengers: The Kang Dynasty and Avengers: Secret Wars being slated for release in 2025, there will be ample time for the MCU to flesh out its various planned storylines throughout MCU Phases 5 and 6. Crossover events are a long-standing Marvel Comics tradition, and the MCU is finally beginning to catch up on these events. Here's everything viewers need to know about every MCU crossover storyline.
Thunderbolts Team-Up
The MCU's Dark Avengers, or even the Dark Illuminati.
Kang's Timeline Wars
The setup for Avengers: The Kang Dynasty begins in Kang let the Avengers win against Thanos as part of his long-term plans for Earth. As the MCU's universes clash, both Ant-Man and the Wasp: Quantumania and Avengers: The Kang Dynasty could introduce several more characters to the MCU's still-growing roster of heroes and villains.
Secret Wars
Even less is known about Avengers: Secret Wars, save for how the movie will follow Avengers: The Kang Dynasty, and that it will be based on Marvel Comics' first real crossover event. In the comics, the first Secret Wars happened in 1984 and was repeated more recently in 2015. The Secret Wars from the '80s focused on how the Beyonder kidnapped Earth's Mightiest Heroes (and villains) to compete on Battleworld, a planet made of different planets from several realities. Meanwhile, in 2015's Secret Wars, Battleworld is not a planet, but a "domain" made from the destroyed pieces of the main Marvel Universe and the Ultimate Marvel Universe. Although Avengers: Secret Wars is one of the many Marvel movies that has yet to reveal its plot or characters, based on Marvel Comics history, Secret Wars is bound to feature the largest cast of characters out of any MCU crossover.
X-Men Vs Avengers - Could It Really Happen?
There's a real chance that the Marvel Comics crossover Avengers vs. X-Men could happen in the MCU. In Avengers vs. X-Men, the two super teams butt heads when the Phoenix Force is revealed to be headed for Earth. While the X-Men believed that the cosmic entity could restore mutantkind following a previous cataclysmic event called the Decimation, the Avengers see the Phoenix Force as the potential end of all mankind. It's entirely possible that, somewhere down the line, Earth's Mightiest Heroes could clash with the Uncanny X-Men, especially considering the many existing X-Men Easter eggs and references in the MCU.
World War Hulk?
The events in She-Hulk suggest that a World War Hulk movie could already be in the works. While the MCU has no Illuminati to exile Bruce Banner into space, and Planet Hulk was already adapted for Thor: Ragnarok, there are still ways for the MCU to adapt World War Hulk. Apart from how She-Hulk revealed that Bruce has been developing long-term psychological methods for controlling the Hulk persona, it's possible that the reason Hulk was summoned to space was that he had a son in Sakaar. With She-Hulk teasing not just the potential MCU debut of Hulk's son Skaar, but also that Bruce could lose control to Hulk again, the MCU's World War Hulk could happen in MCU Phase 6 or 7.
Siege for Thor 5?
Like Avengers: The Kang Dynasty and Avengers: Secret Wars, Norman Osborn's permanent MCU debut. This is because Siege was preceded by Secret Invasion and Dark Reign, in which Osborne becomes a hero to the American people. Following Dark Reign, Osborn used his power and influence to mount a successful invasion of Asgard. In the MCU, this is even more possible considering how New Asgard is located on Earth.
