Ok i know this is old as hell but i just wanted to put mine in as well which probably doesnt matter cause it seems alot of people have the same theory. I think her and her team are feom the future where the vex have just totallt conquered and screwed over all of humanity in all sorts of umiverses, systems and dimensions and studf like that, her team of "guardians" if you will, managed, to escape through a rift or with their own time traveling abilities. (Like the exo) and then proceed to travel through the past, present, and future, and fix key points in history where the vex shouldnt have won. (Wars, small encounters, etc) she travels back to our time to warn us and we know where it goes from there and we think weve seen the end of the vex except the population we still have in our solar system. (No major vex encounters in TDB, HOW, TTK) and just when we think everything is "ok" BOOM she and her team come out of no where and are just like lets go we have to save all of humanity *********time travel********** BOOM the next dlc. We learn more about her and her team, past, present, future, and so on. Just a theory guys dont jump my ass here.