Ellen Brandt was a former soldier working for Advanced Idea Mechanics.
Iron Man 3
Ellen Brandt was a former soldier who was missing her left arm when she entered into A.I.M's Extremis project; the serum was able to regrow her lost limb.
Ellen Brandt bumped into Tony Stark as he was heading into Neptune's Bar and later interrupts him while he was talking to Chad Davis' mother. She started attacking Stark but was killed in an explosion that Tony creates in the kitchen of that very same restaurant in Tennessee.