AnonPig made an interesting theory about the Vex corrupting the Fallen. Read it all here: https://www.bungie.net/en/Forums/Post/206172141?page=0&sort=0&showBanned=0&path=0 I would also like to point out that the Fallen have used Vex tech before, resulting in many possible time-warps and Skolas seeing Oryx. During the duration of the NTTE quest, starting with Daily Paradox, the Vex need you to destroy the Taken in order to save their race. You do so, and even though Praedyth says they won't thank you, they did. The Vex during the final mission of the NTTE quest show future Vex, what would be, not attacking you and instead moving around as normal. You are now in their pattern and they simply ignore you. You are now on neutral terms. Of course, you shoot them and they fire back. You are now out of the pattern and they are upset. It is possible this is the "Vex revenge" I theorized a while back. They discover this... plague. They amplify it for Fallen use and the Fallen get corrupted. Rise of Iron happens. Thoughts?