User blog comment:HarmonyBass/Destiny Ramblings: The Vex and why they haven't won yet. (WARNING! MIGHT GIVE YOU A HEADACHE!)/@comment-160529-20170603080759

its simpler than you make it. You see billions of years ago the Vex were the original inhabitants of mars, they were simple algae lifeforms, but capable of complex thought... but because of their structure, they had no capacity for culture or the transferring of information.

They had to have been uplifted, and that is where A Traveler came in. Putting them in juice boxes and teaching them science, giving them mechanical forms.

but you see, Mars was a dying world and the Traveler does not have patience for a quasi immortal race whose minds exist between machine and renewable organic material. The travelers goals are after all... to harvest the souls of the dying, purge them of darkness, and save those souls from oblivion.

(Unfortunatly... the travelers attempt at creating heaven seems to have created a hell by binding the dark halves of everyones souls to the mortal realm and thus creating the darkness... a darkness that can only be defeated by allowing it back the light which it craves, which is why hive eat and consume light... because the darkness needs it to restore itself... but anyways back to the vex)

As far as the traveler was concerned its work was done, and it left the Vex to their fate... a world with a slowly diminishing atmosphere being torn apart by solar winds, indeed a disturbing fate for creatures dependent on water.

They did not have the technology to spread out among the stars, or to preserve their world. so they struck a deal with the Darkness, and it gave them the technology to essentially create time bubbles, to lock places out of time. Thus they locked their black garden and their vault of glass and all their holdings within pockets of space not affected by time, to keep them safe.

They were eventually freed by the Hive, and they gained access to technology that would allow them to traverse the stars. And since the collapse they have been spreading outward across the galaxy like weeds.

Their Time Travel abilities at most likely consist of being able to travel within the bubbles of time themselves, or exit the bubbles of time at any point in time they wish... which is why they have been active for far longer than they sensibly should have been.

Now... here is the crazy part... Mark my words, when we finally defeat the Vex, we will do so in such a way that causes a cascade effect, deleting their ruins, cities, and technology from all the worlds of mankind as if they were never there.

oddly the records, memories, and effects of their actions will still exist... and while it doesnt make sense, it would seem to be that retro-actively affecting the timeline, only changes the timeline so it was as if it was always that way... from the point it was changed forward.

like... say the year is 2900, august 14... and you change the past, every day after august 14th will be as if the past was changed, but no day before that could act as if it was changed, because... changes only travel forward in time from when they are made.