The Gunslinger (Doctor Who)

The Gunslinger, formerly known as Kahler-Tek, is a minor villain in the Doctor Who episode A Town Called Mercy, He was an experimental Kahler cyborg created by Kahler-Jex.

Personality
Kahler-Tek was strongly motivated by vengeance. He was determined to kill the entire team of scientists that had turned him into a cyborg. However, he demonstrated an unwillingness to harm innocent people. Although he threatened to kill everyone in the town of Mercy, he did not intentionally harm any of the people that lived there, even though they had not handed Kahler-Jex over to him. After Jex committed suicide, the Gunslinger felt that he no longer had any reason to live and decided to go into the desert and self-destruct. The Doctor convinced him to stay and act as a protector to the town.