You know what they say: New year, new Marvel Cinematic Universe movies to watch. While 2025 had a strong start with the release of the highly acclaimed Your Friendly Neighborhood Spider-Man, it wasn't until the release of Captain America: Brave New World that audiences would return to movie theaters to see their favorite Marvel heroes in action.
So now that the movie is finally out, it's time to explain exactly how the President of the United States was turned into a weapon of mass destruction, and what the post-credits scene of the movie was all about.
**WARNING: there will be major spoilers for Captain America: Brave New World ahead**
Why did Thaddeus become the Red Hulk?
Most of the events of Captain America: Brave New World unfold for one specific reason: The Leader wanted to get his revenge on Thaddeus Ross for using him as an asset. See, back in The Incredible Hulk, Samuel Sterns was injured in the head and gamma-radiated blood from Bruce Banner fell into his open wound. This would cause him to mutate and develop an incredible intelligence that allows him to see "every probable outcome" based on statistical probabilities.
Such a gift would allow any man to become the leader of a Nation, and that's exactly what Thaddeus Ross did. He kept Samuel enclosed on a military base called "Camp Echo One" for sixteen years and used his intelligence in his favor to become the President of the United States. While Samuel was promised freedom if Thaddeus ever ran the country, that never came to be — thus making the supervillain plot his revenge.
Ross' heart was failing, and the only one able to stop his death was someone who could come up with a brilliant solution to such a tricky problem (does anyone come to mind?). Samuel agreed to help and came up with pills that could keep the President alive. However, what nobody knew is that they also included small doses of Gamma Radiation that eventually turned a General into a nightmarish monster. As simple as that, the Red Hulk was born.
What happened to Thaddeus after his fight with Captain America?
Against all odds, Sam Wilson is able to hold his ground in a lengthy battle against the Red Hulk. Eventually, the hero tells his opponent to think about his daughter to calm him down. The plan works, and Thaddeus Ross turns into a normal human again after destroying the White House. The president of the United States is then taken to The Raft — a maximum security prison seen during the events of Captain America: Civil War and often reserved for individuals with powers.
At his cell, Ross reveals he accepted full responsibility for his actions and "gave up the office" in the process. That means he's no longer the President of the United States after taking advantage of The Leader's intelligence to earn that position. On the bright side, Thaddeus got what he wanted from the very beginning, which was reconciling with his daughter, Betty Ross (who makes a quick cameo).
There's a big question that remains to be answered, however, and that is: What will happen to Ross now that he isn't taking his pills anymore? It's fair to assume he threw them away considering how they had high levels of Gamma Radiation. However, they were also supposed to keep him alive. So will his heart start to fail once again? Well, fingers crossed it isn't long until we finally figure it out.
Who is The Leader talking about in the post-credits scene?
Okay, this is where things get exciting. Once the dust is settled and The Leader is put behind a cell on The Raft, audiences are treated to a rather interesting post-credits scene. In it, the supervillain tells Captain America that something's coming:
"All you heroes protecting this world. Do you think you're the only ones? Do you think this is the only world? We'll see what happens when you have to protect this place from the others"
This dialog is of course referring to the multiverse, and how the MCU is about to collide with another different reality. Back in the post-credits scene of Doctor Strange in the Multiverse of Madness, Clea reveals that an incursion is about to take place — an apocalyptic-level event where two different universes collide, and one or both die in the process. But who exactly are "the other ones"?
Well, back in the original Secret Wars comic book storyline, heroes from different universes were pitted against each other by the Beyonder. With that in mind, perhaps audiences could see a similar concept play out on the big screen. If an incursion does happen and two different worlds are at risk of being destroyed, then the heroes of each universe would fight for the survival of their home. That's why it would be extremely difficult for the likes of Captain America to protect his world from the "other" heroes who'd also be fighting for a good cause. It's worth remembering that Fantastic Four: First Steps will take place in a branching MCU reality, meaning the four heroes could very well be amongst the "others" the Leader is referring to.
On the bright side, Avengers Doomsday will be released next year on May 1, 2026. So it won't be long until we finally get some much-needed answers about the multiverse and its impending destruction.