The Marvel Cinematic Universe has weaved together the stories of its heroes for 15 years, now. With so many stories and setups in the mix, some have slipped through the cracks. Despite teasing more, future projects never followed up on these plot threads, at least so far.
Some of these forgotten MCU plots threads have faded from memory, not likely to show up again, but some of them could still materialize as new characters and stories get adapted for the Marvel movies and TV shows. As this universe continues to grow and new Phases continue to emerge, these dropped plot points could become very important all over again.
Updated on April 13th by Mayra García: Since the MCU is a very complex universe with dozens of writers and directors, it's only logical that many storylines disappeared without a trace. However, some of these could be picked up again in the future. This has happened already. We updated this list with new storylines from the MCU that went nowhere but have a lot of potential.
10 Scott Lang's Success With X-Con Security Consultants
After putting their lives together, Luis, Scott, Dave, and Kurt realized they were security experts. Given this, they founded a security company, X-Con Security Consultants. Although it had a rocky beginning, by the end of Ant-Man and the Wasp, the company landed its first important client, Karapetyan.
Sadly, Ant-Man and the Wasp: Quantumania didn't follow up on this storyline. Since Luis, Dave, and Kurt weren't in the film, it's impossible to know what happened to their business. All fans know is that Scott's life as a memoir writer and Avenger clearly has no space for X-Con Security Consultants.
9 Black Widow & Hulk's Romance
As of Phase Five, the MCU has a lot of incredible couples that fans love. However, this cinematic universe struggled with romance for a while before getting it right. Avengers: Age of Ultron hinted at a dramatic romance between Natasha and Bruce that eventually amounted to nothing when Hulk left for Sakaar.
Since it made little sense and felt kind of forced, fans are mostly relieved that this strange love story fizzled out. However, this storyline is proof that the first Phases of the MCU had to evolve a lot in order to get to where Marvel Studios is today.
8 Coulson's Death As A Pivotal Moment For The Avengers
When Phil Coulson died at Loki's hands during the Attack on the Hellicarrier in Avengers, this dramatic moment was the key ingredient that finally brought the Avengers together. Since Loki made it personal by killing a beloved Avengers ally, the six heroes joined against the Chitauri.
Agent Coulson's sacrifice didn't last long. He was resurrected during Agents of S.H.I.E.L.D. and went on to star in the series for a while. However, the Avengers never heard from him. What seemed to be an important alliance in the MCU simply disappeared.
7 Nick Fury’s Hunt For Hydra
After S.H.I.E.L.D. fell, Nick Fury informed Captain America that he was going after the rest of Hydra, but this never happened. While Hydra does indeed show up again in Avengers: Age of Ultron, in the form of Baron Von Strucker and Doctor List, nothing else of Fury’s hunt for Hydra has been shown.
Even in the Agents of S.H.I.E.L.D. universe, the show mentions Fury is on the look for agents in trouble, such as Fitz and Simmons. However, Fury never faces a Hydra powerhouse again in the MCU after this. Instead, he's currently about to head the war against the Skrulls in Secret Invasion.
6 Extremis' Long-Term Effects
AIM's exploding super soldiers were a big part of the fight in Iron Man 3, but this kind of enhancement hasn't been seen ever since. It showed up in the Centipede program in Agents of S.H.I.E.L.D., but since that show currently isn't part of MCU canon, it’s hard to know what has become of this process. For that matter, the effects of Pepper Potts’ exposure remain unknown.
Tony Stark said he could “fix” it, but the Extremis effects were never addressed again. Both Tony and Pepper lived a normal life, at least in that regard. Fans have no idea what a stabilized version of Extremis looks like, and since Tony died during Avengers: Endgame, it's likely they will never find out.
5 Baron Mordo's Revenge On Sorcerers
After losing his faith in the Ancient One during Doctor Strange, Baron Mordo decided his new goal in life would be to hunt sorcerers. He even attacked Jonathan Pangborn in the post-credit scene of the film, taking his magic away. After this, he vowed to stop sorcerers, as there were "too many" around.
Fans thought this post-credit scene had set the ground for Mordo to become the villain in the next Doctor Strange installment. However, after vowing to end corruption in the sorcerer circles, Earth-19999's Mordo never appeared again in the MCU.
4 Thor's Search For The Infinity Stones
Witnessing Thor determined to see his vision through in Avengers: Age of Ultron seemed like the perfect set-up for the threats the Avengers would face going forward in the MCU. However, that search for answers never materialized in the following projects.
The only sign of the Infinity Stones in Thor: Ragnarok was the Tesseract, and that didn’t figure in any of the actual stories until Thanos’ attack on the fleeing Asgardians during the mid-credit scenes. Thor’s traveling around the universe was framed as him cleaning up Asgard’s messes rather than a life-or-death search for the next big threat in the MCU.
3 HulkKing's Beef Against She-Hulk
One of the storylines in She-Hulk: Attorney at Law followed Jennifer's search for "HulkKing," the mastermind behind the Intelligencia network trying to mess up her life. In the last episode, She-Hulk discovered the person behind Intelligencia was Todd Phelps, a man baby trying to become a Gamma being too.
Even though the She-Hulk finale was supposed to feature a confrontation between HulkKing and She-Hulk, Jennifer took advantage of her fourth-wall-breaking and stopped the storyline. Although this fits the nature of a She-Hulk series, it would've been nice to know how their battle would've ended.
2 Ghost's Survival
In Ant-Man and the Wasp’s final scene, Hank Pym, Janet Van Dyne, and Hope Van Dyne send Scott Lang into the Quantum Realm to collect healing particles for Ava “Ghost” Starr, so that her phasing condition can be treated. Unfortunately, as Scott leaves, Thanos’ Snap turns the Pym-Van Dyne family to dust.
Scott’s return shaped the race to save Earth from Thanos' doing. However, fans never knew what happened to Ava. Since it was announced that Ava Starr will be a member of the Thunderbolts, it's likely the MCU will address what happened to her after Ant-Man and the Wasp, but at the moment, no one knows about her fate.
1 Kate Bishop Becoming Hawkeye
Hawkeye introduced Kate Bishop to the MCU portrayed by Hailee Steinfeld. Originally a Hawkeye fangirl, she became a hero by helping Clint defeat the Tracksuit Mafia as well as dealing with Yelena Belova, Black Widow's sister, on a journey for revenge.
It has been over a year since Hawkeye's finale, but Hailee Steinfeld hasn't appeared in any other MCU projects, nor is she set to film anything with Marvel Studios. Since Hawkeye actually featured the moment when Clint Barton gives Kate the Hawkeye mantle, fans are curious what this means for each character.