When we first saw this mysterious guardian in the very first mission I though that she would help us later on. However, later on during the first moon mission we see her face and because of the cloak I'm guessing she was a hunter. In the scene that we see her she seems more like a ominous threat. Why else would she let us to fend off the hive horde alone. My theory is she used to be a guardian like us but then her ghost died, and she went rogue trying to steal other guardians light, and become the traveler's worst enemy yet. I don't know but I wanna know. any thoughts, theories.