Relevant Facts: Io is the last place that the Traveler touched before the Collapse. Vex are machines brought to life in a Vex chamber we've seen in a leaked cut-scene, looks like a place we've seen concept art for in Destiny 2. Vex structures all over Io. Vex are capable of travelling through time and building/leaving behind their structures. Theory: What if the last act of the Traveler on Io before the Collapse began was to make the Vex, bring them into being and try to make them a peaceful race to serve the Light. But the Darkness corrupted them and they spread throughout history, then attacked Earth/The Traveler to cause the Collapse? They wouldn't be able to hurt the Traveler before it created them, or else they would prevent their own creation and create a paradox, but once they returned to the time of their creation they'd be able to activate all the machines built across the past and begin to tear down the Golden Age. They also wouldn't be able to put Vex structures anywhere people would find them on earth, the moon, or much of mars as that would change the course of history before we found the Traveler. Anything outside of that wouldn't be too much of a problem as we might expect to find alien structures on alien worlds. So the timeline still works out, and it would give specific reasoning as to why the Collapse began when it did. Sure, they're not talking about "The Darkness" in Destiny 2, but they don't have to give us the full story now. They can just say that the Vex turned on the Traveler. If this is correct though, we have to wonder what their next move is. Did they just get distracted in their worship of the Black Garden's Heart? Are they gearing up for an assault? Why aren't the on earth yet? Is there something else that has to happen across time before they can finish the job? Is that to fulfill part of their "pattern"? It seems like "The Pattern" would be events across history that lead to their victory, so perhaps in exploring Io we'll get to learn more about the beginning of that pattern. Thoughts? Does something in the Grimoire contradict this possibility?