This article contains major Avengers: Endgame spoilers. This is your first and last chance to avoid any of those.
If you take everything for what it is in Avengers: Endgame, Loki died in Infinity War and so he is still dead by the final credits of Endgame because he didn’t appear in the final battle, or did he? (He's totally alive on some other planet btw)
There are so many layers to this movie that you have to question everything twice. And one of its most interesting twists comes one minute before the end credits - an old Steve Rogers. In fact, a 105-year-old Rogers.
Age is not a problem because Rogers can live longer than the average human (120 -130 years tops) and he is mortal. What's important is what this old Rogers means (I will refer to him as Old Cap).
An old and weathered Cap appears in the final scene of Endgame after he has travelled back in time to safely return each borrowed Infinity Stone from the exact moment in past timelines that it was taken by an Avenger.
This is the only way to avoid the creation of alternate realities or prevent the branching off of additional timelines, something that the Ancient One is at first worried about when Bruce Banner comes to fetch the Time Stone.
In current time, which is the year 2023. It in fact only takes five seconds before we see Cap again after he travels back to return the Infinity Stones, traveling right past his fly stamp, which would have allowed an instant return.
But Cap is old now. And to our knowledge, has successfully fulfilled the task of returning the Infinity Stones, with Cap saying: “Once I put the stones back, I thought why not try some of that life Tony told me to get.”
Steve Rogers was always married to Peggy Carter
This is where the twist we never saw coming blew our minds.
After returning the Infinity Stones, Old Cap thinks: heck, I'm going back to 1945 to see my gal. But he does one better, he marries her.
First, we have to acknowledge that the present and future cannot be altered by jumping back in time and Old Cap did not create a branching off of reality to be with Peggy because if he did, there is no way he could end up on that park bench.
His path was simply that he loops back in time in 2023 to 1945 and starts life over from there (having experienced everything from 2012-2023). While the Cap we have always known is frozen in 1945, will wake up in 2012 and avenge stuff.
Cap travels back to 1945.
We know for a fact he didn’t travel back any further than this year because of the song Old Cap and Peggy are dancing to - Kitty Kallen’s rendition of ‘It’s been a long, long time,’ released in 1945.
It’s also the year that Captain America was frozen but more importantly the year Peggy married an unnamed man. Convenient. Unnamed.
In all the references of Peggy throughout the movie franchise this never seemed too important until you consider that that man was in fact Steve Rogers. We just never knew to acknowledge Cap was in her history, because until the last scene of Endgame we did not know that two Captain America’s were simultaneously alive.
Old Cap marries Peggy in 1945 and discloses to her that he is from the future.
At the end of the day, secrecy is Agent Carter’s forte. The secret agent has always had to live a double life. So in the case of Old Cap, she is, in a way, living a triple life. Only herself, and their two children ever knowing (we'll get to the kids).
Peggy Carter References
In Captain America: Winter Soldier we see Steve Rogers visit the Captain America Exhibit at the Smithsonian Institution, where he watches a video of Agent Carter from 1953 talk about the war and Rogers' involvement in it. Agent Carter says:
"Steve...Captain Rogers, he fought his way through HYDRA blockade that had pinned our allies down for months.”
She breaks off after referring to him as Steve, as she would normally call him, correcting it to Captain Rogers.
“He saved over a thousand men, including the man who would... who would become my husband as it turned out..."
We can look at this phrase metaphorically and not literal in a physical sense - Captain America saved (the man who would become Peggy's husband) Steve Rogers from living a life without Peggy Carter by giving himself a second chance after returning the Infinity Stones. A life that always felt robbed from him after he was frozen for 66 years.
She then goes on to say: "Even after he died, Steve is still changing my life.”
She looks down after saying, “Steve is still changing my life,” breaking eye contact, possibly indicative that Steve was still changing her life after death because he was in fact her husband. In this one sentence, she changes tense, speaking of Rogers as if he is in the present, eight years after his (supposed) death. Coincidence? We doubt it.
She also goes back to referring to him as "Steve" after trying to acknowledge him as Captain Rogers.
Later in Winter Soldier, Steve Rogers visits Peggy in a retirement home, the year is 2014 and she is now 93-years-old. Her table-side bed has photos of her two children but none of her husband. A decision we can imagine Old Cap makes knowing that his unfrozen self visits Peggy. And yes, they are Old Cap's kids.
In a conversation that (new) Rogers has with Peggy, regarding his lack of faith in the system, Peggy says:
“You were always so dramatic. Look, you saved the world. We rather mucked it up.”
Rogers replying with, “You didn’t. Knowing you helped found S.H.I.E.L.D. is half the reason I stayed.”
What Rogers says here is a key point we need to address. He is drawn to helping S.H.I.E.L.D. because Peggy is a key member of its creation in the late 1940s. But what we need to consider is that Old Cap may have disclosed to Peggy what happens in the future. Informing Peggy that she needs to help form an intelligence agency that are tasked to maintain national and global security.
An involvement in the agency that would have a 2012 unfrozen Captain America attracted to fight for S.H.I.E.L.D. If Peggy was not linked to the formation and founding of S.H.I.E.L.D. would 2012 Captain America have joined the Avengers?
But more so, we can argue that Old Cap is a key factor in the creation of S.H.I.E.L.D. itself, channeling ideas through Peggy.
Old Cap also knows how much of an asset Hank Pym is at S.H.I.E.L.D. Without Hank, the possibility of the Avengers borrowing the Infinity Stones to amend the destruction's of Thanos does not exist.
Agent Carter is one of the few high ranking officials at S.H.I.E.L.D. that consistently maintains a healthy and good relationship with Hank through his time there (although Howard Stark is pretty good too!). More than likely, Peggy consistently encouraged his work, knowing how important his creation and development of Pym Particles are.
Hank has enough of the organisation by 1989 after his wife dies in a mission (we later know she is alive in the Quantum Realm and rescued in 2018) and leaves. Even up until his last day at S.H.I.E.L.D. Agent Carter supports Hank, telling Mitchell Carson not to make Pym his enemy.
When Old Cap travels back to 1945, he essentially gives up his shield in that moment (symbolically). He is no longer Captain America, he is Steve Rogers living in the shadows. A quiet bystander that must watch from the sidelines, existing only in secret. But living a life he always yearned - a life with Peggy Carter.
However, Old Cap is always a part of the past. What has happened, has happened. Simply put - he was always there from 1945 onward. And who's to say that secret Steve Rogers didn't put on that suit a few times to save the world before 2012? If he did, he just made sure that no one ever saw him.
Peggy Carter sees Old Cap, 1945
Let's go back to the Old Peggy I mentioned before. In this scene, we soon learn that Peggy is suffering from Alzheimer's, after she completely forgets the conversation that she just had with (new) Steve Rogers regarding S.H.I.E.L.D.
This is the pinnacle moment. The moment we see how Peggy reacted 69-years prior, when Old Cap went to find her in 1945.
"You're alive! You... you came, you came back."
"Yeah, Peggy."
"It's been so long. So long." (this is actually Peggy's reply but we can almost argue that her suffering from Alzheimer’s has her repeating the line Steve said in 1945. If you read it as Old Cap's line. It works)
"Well, I couldn't leave my best girl. Not when she owes me a dance."
This here, has to be the conversation that was shared, off screen, between Old Cap and Peggy several minutes prior to us seeing them dance in the final scene of Endgame.
A dance that Steve Rogers has waited a long, long time for.