Bucky is no longer treated like a villain because his name was cleared and the horrible actions of his past as the Winter Soldier haven't been made public, but it's that same past that makes him more suitable for the Thunderbolts.
The best way to explain why Bucky would choose to work with the U.S. government and the Thunderbolts is if they offered him a tempting deal. Knowing that Bucky needs a new arm, Valentina Allegra de Fontaine might offer him a new one in exchange for joining her Thunderbolts team.
THUNDERBOLTS Teaser (2024) With Ryan Reynolds & Sebastian Stan
Who does Bucky Barnes turn into?
Hydra assassin
The Hydra experimentation on Barnes causes him to survive his fall, and he is recaptured by the Hydra wing of the Soviet Union, where he is tortured and brainwashed by Arnim Zola and turned into the Winter Soldier, a mind-controlled super soldier with a metal prosthetic arm.
In Marvel Comics, Bucky takes over as Captain America after Steve does. Because Bucky knew Steve when they were both young, and because he's so important to Steve after he was brought back to life in the comics universe, he's a logical choice for Steve to train and for him to pass the role of Captain America onto.
Later, Lukin winds up playing host to Bucky's long-time nemesis the Red Skull, who utilizes Crossbones, Sin, Doctor Faustus, Arnim Zola, and more of Captain America's enemies to continue tormenting anyone in the shield-slinger's uniform, including Bucky.
James Buchanan “Bucky” Barnes enlists to fight in World War II, but eventually literally falls in battle. Unfortunately, the evil Arnim Zola recovers him and erases his memory, turning him into a highly-trained assassin called the Winter Soldier.
Bucky Barnes was brought back from his supposed death to be a brainwashed assassin called Winter Soldier. Reformed by his friends, he now fights alongside the Avengers.
It has been confirmed that Bucky Barnes (Sebastian Stan) is not going to be in Captain America: New World Order. The character has been a mainstay of the Captain America franchise in the MCU to this point by making appearances in the first trilogy.
Man-Thing had a supporting role in the Thunderbolts after Jeff Parker took over writing the series from issue 138, using the opportunity to alter the membership of the team and making use of Man-Thing.
Baron Helmut Zemo's Thunderbolts. The Thunderbolts' true identities as the Masters of Evil are revealed. Art by Mark Bagley. Baron Helmut Zemo summoned several of his former allies from the prior incarnations of the Masters of Evil during a rescue attempt of Goliath (the former bodyguard to Baron Heinrich Zemo).
Thunderbolts' confirmed cast members include Julia Louis-Dreyfus as Valentina Allegra de Fontaine, Florence Pugh as Yelena Boleva, Sebastian Stan as Bucky Barnes, David Harbour as Red Guardian, Wyatt Russell as U.S. Agent, Hannah John-Kamen as Ghost, and Olga Kurylenko as Taskmaster.
Marvel Studios is replacing the Avengers's team-up movie in the MCU Phase 5 with Thunderbolts, but the premiere superhero team of the MCU could still make an appearance if Marvel Comics' Civil War II storyline is adapted.
Surviving the war and believing Captain America's death, Bucky eventually marries Gail Richards and has a large extended family. During which, Bucky is diagnosed as having lung cancer from chain smoking back in the War. Barnes and Gail both live to see Steve's revival in the 21st century and renews their friendship.
However, before Tony suits up and is about to unleash his rage, Bucky speaks up with an apology: "Tony WAIT! Ok.. I did it..but I wasn't fully conscious about it at the time, they were controlling me the whole time!
Bucky was a hero who fought alongside Steve Rogers in World War Two. But when he was captured and brainwashed, he became an assassin known as the Winter Soldier. It took him a long time to become free and after that, he had a hard time dealing with the things he had to do while he wasn't in control of himself.
In terms of raw strength, Captain America is typically portrayed as being stronger than the Winter Soldier, although the Winter Soldier's combat skills and agility can still make him a formidable opponent.
In December 2025, Nebula went to Earth specifically to steal Bucky Barnes' vibranium arm from him. After defeating him, she succeeded in removing his arm and took it with her back to space, intending to give it to Rocket Raccoon as a Christmas present.
He fought alongside the Avengers in Infinity War and Endgame, he teamed up with Sam Wilson in The Falcon and the Winter Soldier. He's a hero, not a villain or an anti-hero. And yet, Bucky will next be the Thunderbolts team leader.
It's also what he wanted for Steve. Like anybody that ends up traumatized by a war experience, he was affected by it for the rest of his life. So, what felt like a desire there was for a restart - for him and for Steve in a way. It didn't necessarily feel like the shield was gonna be that.
Bucky Barnes, like Steve Rogers, has lived for several decades due to cryogenic freezing and the super-soldier serum. Bucky's life expectancy could potentially surpass Steve's 116 years, depending on circumstances. Despite outwardly aging at the same rate as Steve, Bucky can still live for at least another 80 years.
Black Panther believes Bucky is responsible and chases him down, only to discover Bucky was framed. He offers to help Bucky and Cap and brings them to Wakanda. In a post-credits scene of Civil War, Bucky voluntarily enters into cryostasis in Wakanda until someone can figure out how to fix his brain.
