Michael "Mike" Peterson is a cyborg S.H.I.E.L.D. agent. Peterson was an ordinary man until he was approached by a mysterious group who granted him superpowers through use of the Centipede Serum. However, when he compromised the secrecy of the project, they decided to eliminate him, but they were stopped by a group of S.H.I.E.L.D. agents led by Phil Coulson. Some time later, Peterson decided to join S.H.I.E.L.D. Peterson was later recaptured by the Centipede Project and transformed into the cybernetic operative, Deathlok. He was used by the Clairvoyant to keep people off his trail, including Coulson's Team.
After the downfall of the Centipede Project and the death of John Garrett, he decided to go off on his own seeking redemption for his past crimes as Deathlok. During this period, he was again recruited by a resurrected S.H.I.E.L.D. now led by Phil Coulson and began working directly for him in the continued fight against HYDRA. Coulson gave him the mission to hunt down HYDRA Scientist Doctor List, who eventually captured and tortured Peterson until he was rescued by the former members of Coulson's own team.