The Gunslinger

Kahler-Tek, later known as the Gunslinger, was an experimental Kahler cyborg created by Kahler-Jex.

Kahler-Tek was one of many "volunteers" who were experimented on by Kahler-Jex and his team of scientists to create a weapon to end the war on their homeworld. Tek was transformed into a cybernetic war machine along with countless others who ended the war within a week. However, during that time Kahler-Tek was damaged in the field leading to the resurgence of his original personality. This meant he did not obey his pre-programmed instructions to deactivate after the war ended and began hunting down the scientists who experimented on him.

_{Biography from the Tardis Wiki article, licensed under CC-BY-SA}