Samara

'"By the code I will serve you, Shepard. Your choices are my choices. Your morals are my morals." '

Role in Mass Effect 2
It is unknown who exactly Samara is, but the Quote taken from a Developer Diary, 'By the code I will serve you, Shepard. Your choices are my choices. Your morals are my morals[.]," 'suggests that she may be one of the unofficially announced followers in Mass Effect 2. She is seen helping Shepard search for Thane in one trailer. She may also be an informat to Shephard, as she knows complete security details of Nasreen Danvars private apartment.