Liz Warner, as she first appears, is a decorated FBI agent, and one of the major love interests of Special Agent Don Eppes. Don was originally her instructor at Quantico, and while there seems to have been a mutual attraction, that professional relationship precluded a personal one, according to the rules.
Liz crops up a couple of times, starting with "Longshot", before becoming part of the team and a fixture in Don's love life. She declares the romantic relationship to be definitively over in "Chinese Box", but remains a close and trusted personal friend. Despite the lingering effects of being the boss' ex, Liz builds and maintains strong relationships with David, Megan and Colby, the last after a rocky start. In "Sneakerhead" Liz informed Larry that "Older brother's busy with the State Department. Younger brother's in prison, and father died years ago."
She is extremely intelligent, competent, engaging and loyal, but like Don seems to struggle with building more personal, intimate relationships. Liz is planning to stay with team despite David's 'desertion', at least for the foreseeable future. In "Arm in Arms" she tells Robin Brooks that she (Liz) was just a rebound when Don and Robin broke up the first time (on the show).