James Buchanan "Bucky" Barnes is a character appearing in American comic books published by Marvel Comics. Originally introduced as a sidekick to Captain America, the character was created by Joe Simon and Jack Kirby and first appeared in Captain America Comics #1 (cover-dated March 1941) (which was published by Marvel's predecessor, Timely Comics). Barnes' original costume (or one based on it) and the Bucky nickname have been used by other heroes in the Marvel Universe over the years. The character is brought back from supposed death as the brainwashed assassin cyborg called the Winter Soldier (created by Ed Brubaker and Steve Epting) (Russian: Зимний Солдат, translit. Zimniy Soldát). The character's memories and personality are later restored, leading him to become a dark hero in search of redemption. He temporarily assumes the role of Captain America when Steve Rogers was presumed to be dead. During the 2011 crossover Fear Itself, Barnes is injected with the Infinity Formula, which increases his natural vitality and physical traits in a way similar to (but less powerful than) the super-soldier serum used on Captain America.[2] After coming into contact with the shadowy Outer Circle, Barnes becomes the new Revolution, bringing down the organization from within.[3] Bucky Barnes has been adapted into various media outside comics, including animated series and video games. Sebastian Stan portrays the character across multiple entries in the Marvel Cinematic Universe, including Captain America: The First Avenger (2011), Captain America: The Winter Soldier (2014), Ant-Man (2015), Captain America: Civil War (2016), Black Panther (2018), Avengers: Infinity War (2018), Avengers: Endgame (2019), the miniseries The Falcon and the Winter Soldier (2021), the animated series What If...? (2021-2024), Captain America: Brave New World (2025), Thunderbolts* (2025) and the upcoming Avengers: Doomsday (2026).