Slayback (real name: Gregory Terraerton )is a villain in the Marvel comics and an enemy of Deadpool.
Slayback was once recruited into the Canadian government’s known as Department H which was an organization that was part of Weapon X program’s second phase. The Australian mercenary known as Gregory Terraerton was cybernetically enhanced and endowed with a healing factor derived from Wolverine. Giving the alias Slayback, he undertook missions alongside fellow recruits Copycat, Garrison Kane and Deadpool. Under unrevealed circumstances, he was blown up by Deapool and believed to be deceased.
However Slayback managed to survive due to his healing factor, but it took him several years to fully regenerate. Since then, Slayback swore revenge against Deadpool.