It's not just the Darkness ones (Destiny)

by Ragashingo , Official DBO Cryptarch, Monday, January 26, 2015, 10:29 (3381 days ago) @ Durandal

There's got to be at least some truth to that. We know, for instance, that the Vex mysteriously have some of their machines or tech within all our planets. We know that the Ishtar Collective on Venus were studying nearby Vex ruins, had somehow mapped the Vault of Glass, and even had a Vex unit which they were running test on... or was running test on them...That means the Vex were here at some point before our Golden Age.

Also recall the Mercury Grimoire card... It's part of the Dreams of Alpha Lupi series, with Alpha Lupi almost certainly being The Traveler:

One face blistered, the other plunged into a brutal chill. Is this how it's always been?

You remember hot oceans, nourishing atmosphere. But something transpired, kicked what was wet and fertile into space, stealing away everything of value. Or perhaps what thrived here for a day or for ten million years decided to leave, peeling its wet organics off the bones.

In one of the mission opens our Ghost even mentions that the Vex had begun to take over Venus (around the time The Darkness attacked?) but The Traveler stopped them. Of course we aren't told how it did so... One question that should come up is: If the Vex have some time travel capabilities, and if Humanity (being the heroes of the story) will eventually succeed and survive and thrive, might the Vex eventually switch to our side and help us defeat The Darkness? What about the Fallen or Cabal who both seem more in it for themselves and their own survival instead of being allied with a force of evil?