The blame game could do the trick for a lot of people. Some might blame Doctor Strange for causing it when he accidentally opened up the Multiverse in Spider-Man: No Coming Home then rebounded with America Chavez in Doctor Strange in the Multiverse of Madness. Clea has already let him know the damage was real. Some might blame Wanda Maximoff for crossing different Earths while dreaming, causing destruction in her wake. Then there is Sylvie in Loki, who killed the one man keeping the entire multiverse contained. While it’s easy to point fingers, the truth is more complicated.
Loki Caused The MCU’s First Multiverse Forays
Before Doctor Strange opened up the Multiverse in Spider-Man: No Coming Home, Loki discovered all the information about it that anyone could want. As seen in Avengers: Endgame, a variant of Loki stole the Tesseract and escaped justice after the Battle of New York. This meant that this Loki never found redemption in subsequent MCU films. However, as Loki shown on Disney+, his sacred timeline found redemption, lost his mother, and died trying to stop Thanos. However, when a person cheats their fate, a new branch forms and the multiverse expands. This is why the Time Variance Authority stops the variant and erases the alternate timeline.
This all ended thanks to the Loki variant named Sylvie. While Loki was trying to help save the world, Sylvie just wanted to burn it all down, and she did. Sylvie went to the end of time and slew the One Who Remains, a variant of Kang the Conqueror concerned with preserving the main timeline. With He Who Remains gone, Loki showed that another Kang had taken over the TVA, and now there were endless delays, which would eventually lead to a multiversal war. However, Sylvie was not entirely responsible.
Doctor Strange and Wanda Maximoff pushed things to breaking point
While Sylvie killed the main man protecting the sacred timeline, two other heroes did a lot of damage to the newly created timelines. As no one was stopping new timelines, the importance of protecting each one was important because if people from other worlds showed up, it would fracture that timeline and an incursion was possible. It all started with Doctor Strange, who didn’t even know he was breaching the Multiverse in Spider-Man: No Coming Home. His goal was to help Peter Parker, but the spell went awry, opening up the universe and allowing Spider-Men from other worlds as well as some villains into the MCU world. This puts the MCU in great danger, as Strange learned in Doctor Strange in the Multiverse of Madness.
This film also showed something even more dangerous: dreamwalking, which means leaving its timeline and retaking its variant body in another timeline. Wanda Maximoff made it to countless deadlines as she searched for her children, Billy and Tommy, in hopes of rebuilding her family. Every time she did that, she put this timeline in danger of an incursion. When Doctor Strange encountered the Illuminati on Earth-838, they told him that he posed a danger by being there, even though his variant had already died. Wanda did even more damage during her short stay there. When Clea appeared in the post-credits, she told Strange that the incursions had already begun.
The damage done to the MCU isn’t over yet
Each time an incursion takes place, it destroys the two colliding universes and kills everyone on these Earths. In the comics, countless timelines died before there were only two worlds left. This lead to Secret Wars, which didn’t see the two worlds die but saw them combine, thanks to the mechanics of Doctor Doom. However, before the MCU finds itself in an incursion, more people will likely perform universe-shaking actions. With the arrival of the Fantastic Four, perhaps thanks to the Quantum Realm, they could share some responsibility, thanks to Reed Richards loving to take scientific risks that no human should. It only takes one individual to cause a reversal, and while Doctor Strange, Wanda Maximoff, and Sylvie have kickstarted the coming apocalypse, expect the others to contribute to the mess first. Secret Wars arrives in three years.