Samara

Mass Effect 3 War Asset Entry
The justicars are an ancient asari order dedicated to finding and punishing those who would harm others, They rigidly adhere to the Justicar Code, a comprehensive list of laws. By assaulting the innocent, slaughtering the helpless, and refusing to acknowledge any authority above themselves, the Reapers are an affront to nearly everything the Code stands for. The Justicar Samara has set aside all other responsibilities, pledging to stop the Reapers, even if it kills her.