 The character subsequently appears in "Captain America" #371 (June 1990), #373-378 (July–October 1990), "Guardians of the Galaxy" #28-29 (September–October 1992), "Captain America" #412-414 (February–April 1993), "Thunderbolts" #24-25 (March–April 1999), and "Union Jack" #1-2 (November–December 2006).Jackhammer is a costumed agent/division leader of HYDRA when it was under the leadership of the crime lord Silvermane.When they arranged a kidnapping of Foggy Nelson, Daredevil, Black Widow, and S.H.I.E.L.D.