A Pistolero is another word for a gunslinger. However, there have been several instances over Quelmar's history of specific Pistoleros.
The BackHalls
The BackHalls were full of Pistoleros, which was the name given to the lower level guards who traveled the massive labyrinth looking to shoot and kill known enemies of The City (The BackHalls) before they could return to the City's walls.
The Pistoleros typically wore a shade of green, an outfit given to them by the city itself.
If one was not already an enemy of the city, it was possible to become allied with the city by taking on the role of Pistolero. Anyone who laid their life on the line to protect the city and seek out and kill its enemies had a chance to enter the city's walls and find the portals inside which promised escape from the BackHalls.
Occasionally, someone in the halls would think that they were called the "Pistol Arrows" due to their pistols...but that was wrong, Gail.