Wendy was a waitress from California.
An innocent girl, Wendy was kidnapped by Echo who had been imprinted with the personality of Crystal. After she was kidnapped, and put into the back of a car, which Echo/Crystal also stole, Wendy was taken to Alpha's lair and wiped of her original personality, which was then placed into a wedge. Shortly afterwards, Wendy was imprinted with the personality of Caroline Farrell and allowed to see her original body (Echo, with the imprint of Crystal) so that the two could "meet" and allow Alpha to attempt to convince Echo (and by extent Caroline) that her original personality had abandoned her, similar to the view Alpha holds of his original personality.
Later, when Alpha declares his intent to imprint Crystal/Echo with every personality Echo has ever assumed, Wendy/Caroline attempts to dissuade her from this, but is ignored as Crystal wishes to understand. After the imprint, Wendy/Caroline can only watch (as she is tied to a chair) as Echo attacks Alpha in a rage; her composite event had a different outcome to his own, and Echo was able retain her sanity. During a discussion between Wendy/Caroline and Echo, Wendy/Caroline is shot through the neck by Alpha, and bleeds to death. Wendy's family was later on "generously" taken care of by an anonymous source. (S1: "Omega")
In the original pilot episode, Wendy is a waitress who Echo helps overcome a drug addiction and leave her no-good dealer boyfriend on an altruistic engagement. Later, Wendy is shown to be somewhat recovered in the presence of her mother in the hospital.