Something massive is coming to the Marvel Cinematic Universe. After years of building storylines across films and Disney+ series, Marvel Studios is finally preparing to unleash its next massive crossover event. Avengers: Doomsday (2026) is shaping up to be one of the most important MCU films since the Infinity Saga ended.The project isn’t just another superhero team-up. It’s the payoff to multiple threads that have been developing across the Multiverse Saga. Different timelines, legacy heroes, new teams, and characters from outside the traditional MCU are all beginning to collide.With so many storylines in play, it can feel overwhelming trying to figure out what actually matters before the film arrives. The good news? You don’t need to rewatch the entire MCU to understand what’s coming.Instead, there are a handful of key projects that set the stage for what could be Marvel’s most ambitious crossover yet.Robert Downey Jr. Returns — But Not as Iron ManThe biggest shock surrounding Avengers: Doomsday (2026) came when Marvel revealed that Robert Downey Jr. would return to the MCU. However, the actor who defined Tony Stark (Robert Downey Jr.) for more than a decade won’t be putting the Iron Man armor back on.Instead, he’s stepping into one of Marvel’s most legendary villain roles: Victor Von Doom.Doctor Doom has long been considered one of the most powerful antagonists in Marvel history, and introducing him during the Multiverse Saga opens the door for massive story possibilities. Casting confirmations suggest the film will unite heroes from across the MCU.Sam Wilson / Captain America (Anthony Mackie) is expected to play a major leadership role after the events of his recent film. Brothers Thor (Chris Hemsworth) and Loki (Tom Hiddleston) are set to return. Meanwhile, the Thunderbolts and Fantastic Four will become central figures in the Doomsday plot.Before those pieces come together, however, several key stories help explain how the MCU reached this moment.Credit: Marvel Studios1. Avengers: Infinity War (2018)The road to Avengers: Doomsday really begins with the events of Avengers: Infinity War (2018). This film introduced audiences to the devastating consequences of a universe-wide threat and demonstrated the danger posed by cosmic-level villains.Thanos (Josh Brolin) reshaped the MCU by collecting the Infinity Stones and wiping out half of all life in the universe. More importantly, the film showed how fragile the balance of power truly was. Even Earth’s mightiest heroes struggled to stop a determined villain with cosmic knowledge and preparation.That concept—one powerful figure capable of reshaping reality—feels especially relevant when Doctor Doom enters the picture.2. Avengers: Endgame (2019)If Infinity War shattered the universe, Avengers: Endgame (2019) rewrote it.The Avengers used time travel to undo the Snap, but their actions created fractures across the timeline. These events planted the seeds for the Multiverse Saga that followed. Tony Stark’s sacrifice also left the MCU without one of its central leaders.That absence is significant heading into Doomsday. With Stark gone, the MCU now faces a villain played by the same actor who once saved the universe.Credit: Marvel Studios3. Loki Season 1 (2021) and Season 2 (2023)Few projects are more essential to understanding the Multiverse than the Loki series.The series follows Loki (Tom Hiddleston) as he discovers the Time Variance Authority and learns that countless timelines exist simultaneously. Season 1 introduced the idea that variants of the same character can appear across different universes.Season 2 expands the stakes even further, showing how unstable the timeline has become.By the end of the story, the Multiverse itself is barely being held together. That fragile system could easily become the battleground for Doctor Doom’s rise.4. Spider-Man: No Way Home (2021)The Multiverse officially collided in Spider-Man: No Way Home (2021).When Peter Parker (Tom Holland) seeks help from Doctor Strange (Benedict Cumberbatch), the spell intended to erase his identity opens the door to characters from entirely different universes. Villains and heroes from earlier Spider-Man franchises appear, proving that Marvel is willing to pull characters from outside the MCU timeline.This concept will likely play a major role in Doomsday, where multiple realities may collide.Credit: Marvel Studios / Sony Pictures5. Doctor Strange in the Multiverse of Madness (2022)Doctor Strange in the Multiverse of Madness (2022) pushes the idea of alternate realities even further.Doctor Strange travels through multiple universes while confronting Wanda Maximoff / Scarlet Witch (Elizabeth Olsen). The film introduces the Illuminati, including a version of Professor X (Patrick Stewart), hinting that characters from other Marvel universes are now part of the larger MCU narrative.This moment opens the door for returning X-Men actors and other legacy characters to reappear later.6. Ant-Man and the Wasp: Quantumania (2023)While the film focused heavily on the Quantum Realm, Ant-Man and the Wasp: Quantumania (2023) delivered important information about the Multiverse.Scott Lang / Ant-Man (Paul Rudd) encounters Kang the Conqueror (Jonathan Majors), a villain tied to alternate timelines and reality manipulation. Although the MCU has shifted focus since that film, its exploration of time and dimensional travel still contributes to the larger story.The idea that powerful figures exist across different timelines sets the stage for Doctor Doom’s eventual rise.Credit: Marvel7. Deadpool & Wolverine (2024)One of the most unusual additions to the MCU timeline arrives with Deadpool & Wolverine (2024).The film brings Wade Wilson / Deadpool (Ryan Reynolds) fully into the MCU while also returning Logan / Wolverine (Hugh Jackman). Its connection to multiversal chaos and timeline travel adds another layer to Marvel’s expanding story.More importantly, it signals Marvel’s willingness to merge characters from different cinematic universes.8. Captain America: Brave New World (2025)Sam Wilson officially steps into the spotlight in Captain America: Brave New World (2025).The film shows how the world has changed since Steve Rogers stepped aside. With new global threats emerging, Wilson must redefine what Captain America represents in the modern MCU.His leadership will likely become essential when Earth’s heroes unite again.Credit: Marvel Studios9. Thunderbolts* (2025)The MCU’s morally complicated antihero team arrives in Thunderbolts* (2025).Characters like Yelena Belova (Florence Pugh), Bucky Barnes (Sebastian Stan), and other government-aligned operatives come together for a mission that blurs the line between hero and villain.Their involvement could introduce a new kind of wildcard into the upcoming Avengers conflict.10. The Fantastic Four: First Steps (2025)The arrival of Marvel’s First Family may be the most important setup of all.The Fantastic Four: First Steps (2025) introduces Reed Richards / Mister Fantastic (Pedro Pascal), Sue Storm / Invisible Woman (Vanessa Kirby), Johnny Storm / Human Torch (Joseph Quinn), and Ben Grimm / The Thing (Ebon Moss-Bachrach).Since Doctor Doom is traditionally the Fantastic Four’s greatest enemy, this film likely provides crucial background for the villain’s MCU debut.Credit: Marvel Studios11. Wonder Man Season 1 (2026)Marvel’s newest MCU Disney+ series, Wonder Man (2026), introduces Simon Williams / Wonder Man (Yahya Abdul-Mateen II), a character who blends Hollywood fame with superhuman power.While the show’s tone may differ from that of traditional MCU projects, its exploration of celebrity, identity, and power could easily intersect with the broader Multiverse narrative. Wonder Man is even rumored to make a cameo in Doomsday.12. Spider-Man: Brand New Day (2026)Finally, Spider-Man: Brand New Day (2026) is set to release on July 31, 2026, the last MCU film before Doomsday.It continues Peter Parker’s story after the emotional ending of No Way Home.With the world forgetting who he is, Peter must rebuild his life from scratch. That new beginning could place him directly in the path of Marvel’s next universe-level crisis.Credit: Disney+Honorable Mention: The Original X-Men FilmsThere’s one more group of movies worth revisiting before Doomsday arrives.The original X-Men franchise—including X-Men (2000), X2: X-Men United (2003), and X-Men: The Last Stand (2006)—introduced iconic versions of characters like Wolverine (Hugh Jackman), Storm (Halle Berry), and Professor X (Patrick Stewart).Because the Multiverse now allows Marvel to revisit earlier cinematic universes, several of these actors are expected to appear again.The MCU’s Biggest Collision YetMarvel has spent years building toward this moment. Through time travel, alternate timelines, and multiversal chaos, the MCU has quietly assembled the pieces for a massive crossover event.Avengers: Doomsday (2026) won’t just continue the Multiverse Saga. It may redefine it.And if these twelve projects are any indication, the road to Doctor Doom’s rise is already well underway.The post 12 MCU Projects Fans Should Watch Before ‘Avengers: Doomsday’ appeared first on Inside the Magic.