First appeared in Elektra Assassin #2 in 1986 and was created by Frank Miller and Bill Sienkiewicz. Jonathan "John" Garrett was a former criminal who became a S.H.I.E.L.D. agent and was later given cybernetic enhancements. In Agents of S.H.I.E.L.D., he was a double agent for HYDRA and the main antagonist of the series' first season.