Penny for your thoughts. So the vex, the species itself, is just that liquid goo in their stomach. That's what the black garden has, rivers of vex goo. And the heart kept it flowing. The traveller gave the vex the robo-like bodies a super crazy long time ago. And they used to be super crisp and gold, and over time after being abandoned they rusted and became much older looking. Now atheon. Because atheon came before time, he was a thing before the traveller, so I bet they met, the traveller brought on the golden age, drastically accelerated vextech, and made it possible to create a whole vex army. Thoughts?