USAgent

When Steve Rogers quit his role Captain America, the United States government hired John Walker, the hero known as Super-Patriot, to take his place. When Rogers resumed the Captain America mantle, the government was so impressed by Walker, they offered him a new role as the hero USAgent.

Earth's Mightiest
USAgent defeated Amadeus Cho in the opening round, and Noh-Varr in round 2, but was eliminated by Steve Rogers in the third round.