The heart and brain of Vex power, on Mercury and everywhere, was a set of ever-changing simulations of various possible realities: a maze of places and times that once had been, others yet to be, some still extant, and still others, never to be at all; each as real as real could be, and yet none of them real for very long. It was a tangle of endless forking paths, never twice the same; and at the same time, no more than a single chamber, in which the Vex explored all possible pasts, presents, and futures. Others who entered it, in spite of its masters, called it the Infinite Forest.
Since its discovery, only a few non-Vex had entered that mystery, and returned. Chief among them was a soldier-scholar who called himself Osiris, after an ancient god of death and resurrection. The second after him, was another soldier-scholar named Merioux, who served on and off as Osiris' partner.
Our story now turns to Merioux, on one of his many searches through the Infinite Forest. As he wandered its inconstant corridors and gazed at its erratic screens and relays, a familiar form appeared in the next chamber, and Merioux cried out: 'Hey! Wait!', and dashed after it.
The figure was a woman made of metal, clad in light steel armour and enveloped in a cloak of metallic mesh. Said she: 'We meet again, Warrior of the Light'.
Said Merioux: 'Yeah, we sure do. You were the one on Venus, weren't you? Who warned me about the Vex, the first time I ever saw them! The one who gave me that strange blaster, after my team and I smashed up their installation on Mars;–– the Black Garden;–– weren't you? I still have it, here. We managed to synthesize shots for it, after our engineers analyzed it a little. Where do you come from? How did you know about the Vex? How do you know about our enemies, before we do? Who or what are you, really?'.
The stranger answered: 'So many questions; so little time. But the time has indeed come to answer them'.
Merioux asked: 'Why now?'.
She answered: 'I've studied the Infinite Forest even more than you and Osiris have, and even I don't understand all, but somehow, the Vex have calculated this moment, to be the worst, for them, to let me tell you my secret; and therefore, the best for us. It's a long story. Are you familiar, Guardian, with the Frames? The intelligent machines who do domestic chores around your City, and function as civil servants?
That which you see before you, is a Frame: very much like those you know, in construction, but different in function. We call it a War Frame. I am its operator. I come from your future. This may sound incredible, but it is true. My origin is nearly a thousand years after your time.
In that future, all your present enemies have been defeated, or converted into allies; and so have some others you have not yet met. The Awoken, as the most capable of your races, became the ruling class, and united all this solar system under their rule. The Traveler was dismantled, and its components made into a species of intelligent terraforming engines, known as the Sentients, whom the Awoken (or Orokin, as it came to be pronounced) sent to colonize other systems.
But the Sentients remembered the violation of the Traveler, by which they were made. In time, the Orokin became arrogant and cruel, and the Sentients rebelled against them, and destroyed their empire. Only one Sentient stayed loyal: Natah was her name, and she joined forces with the Orokin scientist Margulis, against her brethren. Over the course of their work, Natah and Margulis became combined into a single intelligence, which called itself, the Lotus.
Meanwhile, Margulis' consort Ballas took the Frames (the only technology the Sentients could not control), and rebuilt them as engines of war. To operate them, he re-created the accident which first created the Awoken, and modified it, to produce a set of children with immense telepathic and psychokinetic powers: enough, as it turned out, to control a War Frame, with split-second timing, even light-years away, and see as it saw and hear as it heard, no matter the distance. These, through a neural interface created by Margulis, became the operators of the War Frames. As you guessed, I am one of them. We call ourselves the Tenno.
In the war that followed, the Sentients were defeated, but the empire collapsed into a dozen quarrelsome factions. We Tenno, now, are trying to bring it all under a single rule, again: that of the Lotus, who still serves as our directress. I, myself, was sent back in time, to study the past, and if possible to rectify it, in our favor;–– which, fortunately for us both, means your favor as well'.
Said Merioux: 'That explains a lot; so, I thank you. But does it mean, then, you're not really here?'.
She answered: 'I am not. Only my Frame is here, while my true self lies in the future, elsewhere'.
Said Merioux: 'Again, I thank you for your story. If you need my help again, don't hesitate to ask'.
She answered: 'I shall ask. For now: farewell!', and vanished into another corridor.