Bucky Barnes or formally introduced as The Winter Soldier. Was first seen in 'Captain America: The First Avenger' as the friend of Steve Rodgers. Rodgers had to witness the death of his friend Bucky near the end of the movie. But what Rodgers didn't know, was that Bucky was alive all this time and was brainwashed by Baron Zemo and was used as a weapon. Rodgers later found this out in 'Captain America: The Winter Soldier' when he had to fight against Bucky. Bucky later learned his true identity and then caused the Avengers to disassemble in (Captain America:Civil War)after Tony Stark(Iron Man)found out that Bucky killed his parents in an incident that happened before Tony became Iron Man. After the Avengers disassembled, he came back in (Avengers:Infinity War)to fight off the mighty titan Thanos. He also came back in (Avengers:Endgame) to fight Thanos one last time. He was played by Sebastian Stan.