Agent Jack Truman, aka Agent 18, was SHIELD's best manhunter. After taking some relaxation time in Sudan, he was contacted by SHIELD to hunt down Nathan Summers, Cable. After successfully capturing the mutant using Zzzax (and despite interference from SHIELD agent Larry Young), Truman decided to help free Cable after discovering he was being used to try and create robotic soldiers. Truman was severely burnt and all his senses were destroyed except for his sight. SHIELD scientists operated on him without Nick Fury's approval. He later took on the eponymous name of the aforementioned experiment; Operation: Deathlok.
Jack Truman first appeared, simply as Agent 18, in Cable #59 and was created by Joe Casey and Jose Ladrönn in 1998. He first became Deathlok in 1999's Deathlok #1 which was also written by Joe Casey and drawn by Leonardo Manco.
Mayor Story Arcs
As Deathlok, Truman received his own on-going series as part of the M-Tech brand. It lasted 11 issues. The first three issues detailed his origin following his escape from SHIELD because of the Red Skull. The series saw the new Deathlok, his body utilizing components from Machine Man, battle against the likes of Puff Adder, the Ring Master and the Clown. At the end of the series, Truman was eventually able to telepathically trade minds with his former rival colleague, Larry Young (who had since been fired from SHIELD), while trapping Young in the Deathlok body.
Recently, Truman appeared in the Vengeance mini-series. He was still trapped in Larry Young's aged body and assisted the activities of the new Teen Brigade. Truman, still living as Larry Young, was approached by the Defenders' Kyle Richmond and Joaquin Pennysworth when he appeared linked to a Government conspiracy involving the new Teen Brigade and the Young Masters. He was discovered to have been leaking classified information to the Teen Brigade in hopes of them "cleaning up the mess" that was otherwise overlooked by SHIELD and others. Truman helped mentor Ultimate Nullifier and the Teen Brigade for a battle against the Young Masters who sought to assassinate Kristoff Vernard.