John Walker’s New Superhero Origin Makes Him A Dark Iron Man Mirror
John Walker makes himself a new Captain America shield in The Falcon and the Winter Soldier episode 5, and in the process becomes a dark mirror of Iron Man. First introduced at the end of The Falcon and the Winter Soldier episode 1, John Walker was the new Captain America as chosen by the U.S. Government, immediately making for a contrast to Steve Rogers. Over time, he became a look at how Captain America could've went horribly wrong, but he now reflects the legacy of Iron Man as well.
Following on from his murder of Nico, Walker has to face some level of punishment for his actions. While he isn't court-martialled, due to his military record, he is stripped of the Captain America title. Walker's mental state was already in question, since he watched his best friend die, took the super soldier serum, and was struggling to live up to Steve Rogers, but this made it much worse. However, even with that (or rather, because of it), Walker has no intention of actually just giving up being Captain America.
The Falcon & Winter Soldier episode 5 post-credits scene finds John Walker making his own Captain America shield. While it's obviously a moment connected to that particular character, the way the moment is framed very much links him to Iron Man as well. The use of scraps of metal - and the clanging around - call back to Iron Man building his very first suit in a cave; it's a DIY approach to superheroism, and the shots of Walker wielding a hammer to do so feel very similar to those of Tony Stark. As if that weren't enough, though, The Falcon and the Winter Soldier episode 5 also puts a riff on the classic "I am Iron Man" line, with Walker yelling "I am Captain America."
While Walker's more directly linked to Steve, it does make some sense to connect him with Tony Stark as well. Given it was Iron Man who led the support for the Sokovia Accords, then the fallout from that decision and the civil war that ensued is still informing the MCU even today, leading to a new government-controlled Captain America. And while Walker doesn't have much in common with Steve, he does share some of Tony's more negative traits - in particular his ego - that show not only how Cap could go wrong, but further turn him into a dark mirror of Iron Man. What stood Iron Man apart, of course, was that he grew into the man who would be the hero and be prepared to make the ultimate sacrifice; Walker would have done that for his country, evidenced by his Medals of Honor, but has been twisted away from that sense of valor.
It's interesting too that this comes in The Falcon and the Winter Soldier episode 5, which opens with a 2-on-1 fight scene that echoes the end of Captain America: Civil War. Once again involving Bucky, he and Sam serve as the new version of him and Steve; with Walker the man they're ideologically opposed to and wanting to beat, then he becomes the Iron Man in that version of that fight scene. To then end with him building his own shield just makes him even more like a dark Iron Man.