Not much is known about Yvette. She is the main one in charge of the small-time raider gang known as the Scorpions, responsible for slinging chems outside of Vegas. Petty and overconfident, the actions of the Scorpions frequently get themselves into fights with the Fiends.
Like other raider gangs, the Scorpions will attack strangers on sight.
Ammunition for the Scorpions: At some point in development Yvette would have been the source of an optional, unmarked quest to aid the Scorpions gang in obtaining "a steady supply of ammunition from the NCR quartermaster at Camp McCarran." This quest was never fully implemented, but some resources related to it remain, in particular a note titled "Ammunition for the Scorpions."