White Wolf (MCU)'s History
Sergeant James Buchanan "Bucky" Barnes was a former soldier of the 107th Infantry Regiment and the best friend of Steve Rogers, since childhood. Barnes was conscripted and assigned to the 107th in 1942. His regiment was captured by the forces of HYDRA, but Barnes along with what remained of his regiment were rescued by Rogers, who had become Captain America during Barnes' military absence. Joining forces in the continuing war, Barnes and Rogers formed the Howling Commandos to battle the Red Skull's forces. During an attempt to capture HYDRA scientist Arnim Zola, Barnes was caught in an ambush and plummeted hundreds of feet from the HYDRA train. As no body was ever recovered, he was then presumed dead, but officially listed as MIA.
Unbeknownst to his team, Barnes had actually survived the attack on Zola's train, albeit with the loss of his left arm. Brainwashed and armed with a new cybernetic limb, Barnes ultimately became an enhanced HYDRA operative known as the Winter Soldier. Over the next several decades, he would eliminate anyone who posed a threat to HYDRA, including his former ally Howard Stark and Howard's wife, Maria. Between his missions, Barnes would be put into a cryogenic stasis to ensure his longevity. Over half a century later, when he was ordered by current HYDRA leader Alexander Pierce to assassinate S.H.I.E.L.D. Director Nick Fury, the Winter Soldier was unexpectedly confronted by his old friend, Steve Rogers, triggering him to then begin remembering his prior life.
In the wake of the Battle at the Triskelion, the Winter Soldier went on the run from HYDRA on a mission to remember his past and end his long, violent history. However, Barnes was then framed for the terrorist bombing, which claimed the life of T'Chaka, the King of Wakanda, among others. As Black Panther sought revenge for his father's death, Barnes was repeatedly saved by Captain America, sparking the Avengers Civil War as a team lead by Tony Stark was sent to capture him. It was later revealed that Helmut Zemo had organized the Civil War, all so Zemo could reveal that Barnes had murdered Stark's parents years earlier. Having survived Tony Stark's revenge attempt, Barnes was then taken in by the nation of Wakanda, where he was allowed, by T'Challa, to be frozen until his mind could be freed of HYDRA's programming.
Barnes gradually recovered with help from T'Challa's sister Shuri. When Wakanda came under threat from the Mad Titan Thanos for harbouring the Vision, who was currently in possession of the Mind Stone, Barnes joined T'Challa and the Avengers to help fight off the threat, receiving a new Vibranium arm. Despite their best efforts: managing to kill all of Thanos' forces; when Thanos arrived at Wakanda personally, he effortlessly overpowered Barnes and the heroes in his way and victoriously assembled all the Infinity Stones. Barnes was subsequently disintegrated after Thanos erased half of the life in all the universe.
In 2023, Barnes, along with all other victims of the Decimation, were resurrected by the efforts of Hulk and the Avengers. Barnes then participated in the Battle of Earth, fighting alongside Rocket Raccoon. In the aftermath of the battle, he bid Rogers farewell as Rogers traveled back in time to the 1940s and was present to witness Rogers, as an old man, return to choose Wilson as his successor.