James Buchanan "Bucky" Barnes

James Buchanan "Bucky" Barnes, also known as the Winter Soldier and the White Wolf, is a fictional character in the Marvel Cinematic Universe (MCU) media franchise, based on the Marvel Comics character of the same name. He is portrayed by Sebastian Stan. Bucky and Steve Rogers were childhood best friends who served together during World War II. Bucky was then transformed into a brainwashed Hydra super soldier and assassin known as the Winter Soldier. He was eventually cured of his programming in Wakanda. After Steve Rogers' retirement, Bucky partnered with Sam Wilson to support him as the new Captain America. He will return in the upcoming film Thunderbolts with a lead role.