Agent "Tex" Texas from Red Vs. Blue, a woman who could probably beat up Chuck Norris. (heavy spoilers follow):: Apparently, she was the girlfriend of the Director of Project FREELANCER and a member of the UNSC army. After she was KIA, the Director couldn't get over her and, so distraught, made an AI of her, cobbled together from all his memories of her and plunked her into a robot body, where she was only loosely aware of her true nature. Her badassitude comes not from her ability to beat the entire Blood Gulch crew, as pretty much anyone can do that, but her amazing prowess when fighting the innumerable other foes she faces, from religous zealots, to elites to other FREELANCERs, she survived all of them, though she was never able to execute a killing blow due to a flaw in her programming. Go watch the show, she appears in most episodes until she gets killed off in the end of season five, then brought back, then obliterated from existence. Ouch.
Most definately the only member of this list to have their legacy wiped out, she still managed to be an incredible badass while she lasted.
Agent Tex, you gotta fetish, or somethin'