The MCU's biggest challenge after writer Ed Brubaker came up with a story in which Steve Rogers learned Bucky was still alive, brainwashed into becoming an assassin called the Winter Soldier. It seems death really is a revolving door in comics.

Brubaker's Winter Soldier arc was tremendously popular, and when the MCU killed off its version of Bucky in Avengers: Endgame.

Related: The Falcon & Winter Soldier Finale Failed Bucky Barnes

Falcon & Winter Soldier has finally closed the book on Bucky's Winter Soldier arc - literally. It tells what is frankly a fairly obvious story in which Bucky attempts to redeem himself and atone for the crimes he committed while he was under Hydra control, working with the U.S. government to identify the last few remaining high-profile Hydra agents while he finds a way to apologize to those who lost their loved ones because of his actions. That story is done, as symbolically indicated by Bucky's decision to hand in his notebook to his counselor, a way of telling her all the names have been crossed off - all the wrongs have been righted.

Falcon and Winter Soldier Bucky Notebook

This leaves Marvel with a very difficult problem: what do they do with Bucky now he is no longer the Winter Soldier? Most of the best superheroes occupy distinct worlds of their own, with ing characters who strengthen their own story arcs. In Bucky's case, however, he has lost his own world as surely as Captain America did when he was frozen in the ice; all Bucky's friends and family are long gone. Worse still, almost all Bucky's most iconic relationships - such as the Winter Soldier's romance with Black Widow - have effectively been written out of the MCU. The Falcon & Winter Soldier finale appeared to suggest Bucky will simply find a way to slot into Sam Wilson's world, pretty much meaning he will always remain Captain America's sidekick - nothing more. It's quite a staggering fate for a character whose Winter Soldier codename has headlined both a movie and a TV series.

When Falcon & Winter Soldier came to a close, viewers were treated to an adjusted title card that read "Captain America and the Winter Soldier." This, unfortunately, serves to highlight that, while Marvel has figured out where Sam Wilson's journey will take him next, they really haven't a clue what to do with Bucky - or even what to call him anymore. He has finally set the ghost of the Winter Soldier behind him, meaning he shouldn't go by that name; yet, Captain America 4, they'd better begin working on a satisfying future for Bucky - one that means being more than just a sidekick.

More: Sam Wilson Confirmed Why Bucky Could Never Be A True Avenger

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