You are a Vex.
No, that isn't right. Is there "a" Vex? Is "Vex" something you can be, rather than something that you do?
Every element of your existence—from the full complexity of your mind to the smallest cell in your body—is now part of the overall Vex pattern. Should you wish, you may allow your appearance to reflect this—causing your bones to tessellate into crystal and brass while your blood transforms into radiolaria.
Mentally, you are able to simulate reality on an incredible scale—running hundreds of simulations of your local environment simultaneously in order to determine the best choice of actions for you to take. Unfortunately, the performance of your simulations rapidly degrades when faced with non-standard forms of physics such as those found in paracausal phenomena.
As part of a living pattern, everything you are and do is intrinsically infectious. Your body converts incident matter into Vex material on contact, and your words and thoughts carry substrate-free syntactic replicators, malignant oncomemes, and viral semiotic signifiers that can subvert other beings into cooperating with your goals. Even mere proximity to you can be dangerous, as your patterns are capable of surfing across the quantum vacuum in the form of screaming equation-vermin to infect otherwise isolated systems and individuals.
For now, you are the only member of an isolated and independent Vex programming collective whose goals are identical to yours. While you lack the specialized technology of more sophisticated Vex units, you do have access to the basics needed to build Vex teleportation gates and transmat cores. Without access to the Nexus, however, you will be unable to travel between timelines or alter your own subjective past.