Bucky’s Winter Soldier backstory makes his reaction to Sentry in the MCU’s Thunderbolts* all the more devastating. As one of the MCU timeline’s oldest heroes – and previously one of its most iconic antagonists – Bucky Barnes’ history is a key part of the MCU’s movie empire.

2025 has only made this more true for the franchise, as Bucky is set up as a congressman in Captain America: Brave New World, and then becomes a member of the New Avengers by Thunderbolts*‘s ending. However, looking at Barnes’ Winter Soldier story and how it links to Sentry’s own, it seems this surprising trajectory was very much inevitable.

Bucky & Sentry’s Stories Are Far More Similar In The MCU Than It Might Seem

While Bucky and Bob are very different characters in most senses – in terms of their contrasting personalities, their differing powers, and their respective roles in the MCU up to this point – their stories still manage to be very similar. Indeed, the circumstances that gave Barnes his Winter Soldier moniker and Bob his Sentry тιтle clearly mirror one another.

Both Bucky and Bob are turned into weapons via super soldier serums and controlled by shadowy figures – though for Bucky, this is via HYDRA, whereas for Bob, this is via Valentina and the OXE facility that gave him powers. Similarly, both are manipulated into doing terrible things – Bucky through direct brainwashing, and Bob through Valentina using his past against him.

This makes the duo’s stories tragic in the same sense too, as it’s clear both feel guilt for what they did while being manipulated. On the plus side, though, Bucky and Bob are also both brought back from the brink by their friends – with Steve eventually managing to break the Winter Soldier conditioning, and the Thunderbolts helping Bob break the Void’s control.

It’s almost impossible to imagine that Bucky doesn’t see the parallels between him and Bob, even if his Sentry transformation didn’t involve outright brainwashing. Indeed, given how similar Valentina is in many regards to Alexander Pierce – who commanded Bucky while he was the Winter Soldier – Thunderbolts*‘s Sentry story has more than one parallel to the story of The Winter Soldier.

Bucky’s Winter Soldier Backstory Further Explains Why He Dislikes Val (& Cares About Bob)

With Valentina, like Pierce, being an outwardly affable diplomat of sorts who secretly harbors more sinister motives – and who believes these motives are justified in terms of their own concept of the greater good – both Bucky and Bob end up being essentially casualties of their schemes, and are dispatched to try and kill the heroes of two respective MCU installments.

Since The Falcon & The Winter Soldier underlined the guilt Bucky still feels about his Winter Soldier days, it makes particular sense Thunderbolts* seems to depict him with a particular distrust for Valentina, and also seems to depict him as wanting to give Bob a chance despite both Sentry and the Void putting him through the proverbial wringer.

Bucky’s seemingly horrorified reaction in the scene wherein Val reveals Sentry to the Thunderbolts makes even more sense through this lens. Valentina essentially ends up showing Bucky she’s made her own more powerful version of the Winter Soldier, and reveals she’s looking at severing Bob’s few remaining ties to others via having him kill the Thunderbolts.

This also adds an extra dose of emotion and meaning to moments like Barnes deflecting an attack aimed at Bob in the iconic chicken costume fight scene, or him being the first to stalk after Valentina in the Thunderbolts* movie ending. More importantly, this all may have also reinforced another decision Bucky made later down the line.

Bucky Shared History With The Thunderbolts May Explain Why He Remained Why The New Avengers

Given Bucky’s bond with Sam Wilson – and the Captain America: Brave New World ending establishing that Wilson is forming his own Avengers – Barnes’ decision to stay with the New Avengers may seem an odd one. However, Bucky’s story and past tragedies being far closer to Bob’s backstory and the histories of the team’s other members shed some light on this.

While Valentina literally announcing Bucky as part of the team to a live audience is likely play a role, Barnes’s ability to relate to stories like Bob’s looks to have given him further reason to remain on the team. Ultimately, a lot of the complicated redemption arcs the team’s members are going through are simply newer versions of Barnes’ own.

Inversely, it’s also likely that Bucky wished to stay with the New Avengers in order to protect them in a sense from Val. The Thunderbolts* ending sees Val enter a wary truce of sorts with her newly-christened New Avengers, but her scheming nature means this truce is a naturally risky one.

With the New Avengers set to next appear in Avengers: Doomsday, it seems the 2026 movie could soon further expand on Bucky’s bonds with Bob and the other members of the Thunderbolts* team. Ultimately, it wouldn’t be a surprise if Doomsday further highlighted how similar Barnes is to his teammates, especially in terms of his tragic past.