Notable info: Capable of transtemporal warping.
Former bearer of The Stranger's Rifle/No Time To Explain
The Exo Stranger is an Exo that roams the wild without a Ghost. Her purpose and intentions are unknown, but she appears to be interested in the player's activities and keeps tabs on them when they venture outside of the City.
The Stranger appears to be working for an unknown faction who know more about the war against the Darkness than Guardians do. She possesses much technology that even Ghosts don't fully understand; she is capable of appearing and disappearing out of reality, and her weapon has parts that "shouldn't yet exist." Those who have seen her are divided on who she is: some claim she is the remains of a forgotten Exo squadron fighting a long ago war while others believe her intervention has saved their lives. A few believe she is a hallucination caused by exposure to Vex technologies.
At an unknown time she encountered Rasputin, who recognized her but did not understand her purpose; and thus asks her how he could imitate her. This meeting may have occurred during one her numerous reappearances to stave off an unknown future, as in another point in time—or times—she observes the Traveler and the Last City falling to numerous unknown enemies, and among the dead sees herself appearing occasionally.