5 Marvel TV Episodes You Have To Rewatch Before Seeing Avengers: Doomsday

It's been less than a decade since Earth's Mightiest Heroes defeated Thanos (Josh Brolin) in "Avengers: Endgame," and they're already set to take on another all-powerful supervillain. 2026's "Avengers: Doomsday" will bring an army of costumed crusaders together to face Doctor Doom (Robert Downey Jr.) as he wages war against the multiverse.

So far, it's not completely clear what Doom's ultimate goal actually is, but one of the movie's recent trailers sees Sue Storm (Vanessa Kirby) explain that he used to be "kind" and "caring." This apparently changed following an unspoken tragedy that left him "broken," with footage showing Doom staring longingly at a painting of a woman and her child, implying that the Latverian villain has somehow lost his family along the way. In the same trailer, Doom tells the heroes that they have "lived stolen lives" and now "must give them back."

While it seems like the film will have to do some heavy lifting to make its villain work, the MCU has at least laid some ground for his arrival. Here are the Marvel TV episodes you need to rewatch before "Avengers: Doomsday" arrives in theaters.

Let's start with "Loki." Marvel's God of Mischief is set to return in "Avengers: Doomsday," and it's vital to know what he's been up to in the time since movie audiences last saw him in "Endgame."

The premise of the series rests on the variant of Loki (Tom Hiddleston) who escaped during the time heist carried out by Tony Stark (Robert Downey Jr.) and his fellow Avengers. After getting his hands on the Tesseract and disappearing through a portal, he's picked up by the Time Variance Authority, an organization that works to keep the flow of time intact from beyond the edges of our universe.

Importantly, the early stages of "Loki" are built on the idea that new variants of old characters can be created when a timeline deviates from specific events that are "supposed" to happen. This creates a new reality, potentially causing significant problems for the greater multiverse. Considering Robert Downey Jr. is returning to play Doctor Doom in "Doomsday" having spent a decade as Tony Stark, it's not impossible to imagine that he could be some kind of variant of the hero we all know and love. Only time will tell — but the beginning of "Loki," at least, could give us a few clues.

Considering "WandaVision" is one of the best Marvel Disney+ shows out there, it's maybe unsurprising that this also deserves a rewatch before "Avengers: Doomsday." The series establishes just how powerful Wanda Maximoff (Elizabeth Olsen) really is, showing how she tiptoes the line between hero and villain after the events of "Infinity War" and "Endgame." Wanda takes over the town of Westview in order to create an idyllic life for her fake family — but when she realizes the damage she's caused in the final episode, she brings down the illusion and loses everything all over again. Her sons' souls seemingly disappear, and the version of Vision she created fades away into nothingness. 

While "WandaVision" isn't a multiverse story, the show establishes the power of magic in the MCU, and it seems like Doom will be using that kind of power to his advantage in "Doomsday," given the witch-like runes that decorate his armor. As for Wanda herself, she returned with a vengeance in "Doctor Strange in the Multiverse of Madness" before appearing to sacrifice her life to destroy every copy of the Darkhold in the multiverse. But remember: No body, no death! Since Doom specifically mentions the Avengers living "stolen lives" in the "Doomsday" trailer, could that mean he's discovered how Wanda's meddling affected the multiverse? Could Wanda herself come back at some point in the movie? We'll just have to wait and see.

If we're continuing the streak of stolen lives and powerful magic in the MCU, the ninth episode of "Agatha All Along" is another must-watch story. Not only is "Agatha All Along" an underrated superhero show in general, but it also continues the "WandaVision" storyline by revealing that the soul of Wanda's younger son, Billy, ended up in the body of William Kaplan (Joe Locke). When she shattered the illusion in Westview, Billy used his own magic to reincarnate into the body of the teenager.

The final episode of the series reveals that Billy is so powerful that he unknowingly created an entire magical realm — the Witches' Road — out of an ancient children's song. Not only that, but he and the ghost of Agatha Harkness (Kathryn Hahn) end the show by starting the search for his brother, Tommy, whose soul he also saved. Clearly, Wanda and her family have caused plenty of damage in the MCU universe and the wider multiverse, and it'll be interesting to see if Doctor Doom holds them accountable on the big screen.

The end of "Loki" Season 1 blew plenty of minds back in 2021. Not only did it confirm that the MCU would be swandiving into the multiverse going forward, but it also revealed Jonathan Majors as He Who Remains, a variant of Kang the Conqueror. Considering this was only two years after Marvel had wrapped up the Thanos storyline in "Avengers: Endgame," it was impressive that the company was already moving onto the next big threat so quickly. While that didn't pan out, the Season 1 finale of "Loki" still provides vital context about time travel and the multiverse.

In this episode, He Who Remains tells Loki and Sylvie (Sophia DiMartino) that the multiverse hinges on a single reality known as the Sacred Timeline, and that he kept this timeline in check following a huge multiversal war between different variants of himself. Under his guidance, the TVA would "prune" any branch that spun off from the Sacred Timeline. 

The first season of "Loki" ends with Sylvie choosing to send Loki back to the TVA before killing He Who Remains. But Sylvie's actions have catastrophic effects on the multiverse, as Loki discovers a huge statue of Kang the Conqueror in the TVA. While this gets undone in Season 2, Kang's meddling with time has been so drastic that it will be downright bizarre if Doctor Doom doesn't acknowledge it in "Avengers: Doomsday."

"Loki" has featured heavily in this list thanks to the TVA's unique place in the multiverse, but the most important episode to watch before "Avengers: Doomsday" is the Season 2 finale, "Glorious Purpose." In this episode, Loki realizes he can't stop the Sacred Timeline from collapsing because there are simply too many alternate timelines to deal with, and the TVA's machinery can't keep them in check. Instead, he chooses to step out into the cosmos and physically hold all of the branches together himself.

This puts the former villain at the heart of the multiverse and makes him an integral element in keeping every reality stable. Since Doctor Doom's war on Earth's Mightiest Heroes will include alternate realities and different Earths, knowing Loki's side of the story so far is incredibly important.

On top of that, the end of "Loki" Season 2 also functions as a way of writing Kang the Conqueror out of the picture, as the episode ends with Mobius (Owen Wilson), Hunter B-15 (Wunmi Mosaku), and the rest of the TVA working to prune any Kang variants from the multiverse. This is a highly useful piece of information to know, considering Kang was meant to be the next big bad for the Avengers prior to the firing of Jonathan Majors. Now, all eyes are on Doctor Doom — and whatever evil he has planned for the multiverse.