Bucky Barnes

Bucky Barnes was the sidekick of Captain America. He was created by Joe Simon and Jack Kirby and first appeared in Captain America #1 (1941).

Origin
James Buchanan "Bucky" Barnes was the mascot at Camp Lehigh. One night he walked in on Steve Rogers as he was taking off his costume and discovered that he was Captain America. Bucky then became to sidekick to Captain America. Bucky also became a member of the the Invaders, The All-winners Squad and the Kid Commandos.

Death
In the closing days of World War II Captain America and Bucky tried to stop Baron Zemo from stealing an experimental drone plane. Zemo manages to launch the drone which has an explosive on it and Captain America and Bucky jump on. Bucky tried to defuse the bomb but was unsuccesful. Steve fell off the drone and Bucky perished when the drone exploded.