Serving in a war, Burt Kenyon saved his comrade Frank Castle's life. Both Castle and Kenyon assumed this was a life debt. Kenyon was released from service because he was deemed psychologically unstable.
Upon returning to the USA, Kenyon took work for the Maggia as Hitman, a villainous analoge to Frank Castle's emerging vigilante identity of the Punisher. On his first assignment, Hitman ran afoul of Spider-Man by taking a contract on the hero's life. Spider-Man passed his tracker onto the Punisher who began to hunt his former friend.
During Kenyon's next assignment to assassinate J. Jonah Jameson, Hitman, Punisher, and Spider-Man held a final battle at the Statue of Liberty. When Punisher chose to save an injured Spider-Man and Jameson hanging over the monument's edge over his former ally in similar dire straits, Kenyon released him of his debt to him from the war and let go, falling to his death.
Several years later, Hitman was one of the many friends or foes of Spider-Man returned to life by the Jackal using his cloning. Jackal intended to use the return of these people as an incentive to make Spider-Man join his enterprise. Most of the people cloned back to life by the Jackal died shortly afterwards, but Hitman was one of the few survivors, and continued working as a mercenary. Kenyon devised a way to constantly cheat death, by establishing a system in which his consciousness was uploaded to a cloud and then downloaded into a new body whenever necessary.
