John Walker

John Walker, aka U.S. Agent, is a Marvel Comics superhero.

History
U.S. Agent was fighting Gajeel Redfox when he accidentally threw his shield at Aki Izayoi's friend, angering Aki. Aki got into an argument with U.S. Agent, which was interrupted when Gajeel grabbed Aki and used her as a hostage. Walker observed Aki teleport herself and Gajeel away.