Violet

 is one of the three Fiend bosses from the quest Three-Card Bounty given by Major Dhatri from Camp McCarren. She's a sniper who has a lot of dogs, and is living in a fort made from abandoned campers southwest of South Vegas Ruins West Entrance in 2281. Her fort is almost one full grid away directly west of Vault 3 on the World Map.

Background
Violet is accompanied with multiple guard dogs; depends on level. She is located near the Poseidon Gas Station in the trailer park. Since the quest advises you to travel through the South Vegas Ruins West Entrance, you may encounter Cook-Cook along the way--so be prepared for him. She is apparently a cannibal, and feeds her dogs human flesh as well. One of her dogs Violetta also has a brain that you can take from her corpse. Presumably her brain can be put into one of the robot dogs later in the game.
 * The Bloody Mess Perk also causes havoc with this quest. Try to complete this quest before getting the perk. Also applies to the other fiends.
 * Try to target the legs and kill her that way. Often the legs get blown off and her head is OK to take.

Loot
Violet's fort (unmarked location) has some good loot, especially
 * Nuka-Cola Quartz
 * Many temp-status magazines
 * Lots of sniper ammo
 * Decent Armor
 * Violetta's Brain

Appearances
appears in Fallout: New Vegas.