A fictional gunslinger
In the Ancient West, a gunslinger or gunfighter was an individual who was especially skilled with a gun, was an expert at the fast draw, or participated in a gunfight.
According to Alexander Rozhenko, the hologram Eli Hollander was "the meanest and the toughest gunslinger in the West." He warned his father Worf that he "[had] to watch him. He's fast."
After the holodeck replaced the original character with the image and abilities of Data, as well as the fact that the holodeck safeties were off, Deanna Troi warned that "There's a gunfighter out there who has the speed and accuracy of an android. And in two hours, he's going to try to kill you." (TNG: "A Fistful of Datas")
As the USS Enterprise created an emergent lifeform in 2370, the holodeck created several characters that Troi theorized to be individuals who "represent different aspects of the ship," stating for example, that "the gunslinger could be the weapon system." (TNG: "Emergence")