WandaVision: 8 INSANE Fan Theories For The Final Episode
2. White Vision Is Actually Ultron
As incredible as seeing Vision Vs White Vision would be, it could be a whole lot better if it turns out that the latter is actually Ultron. The villain of the second Avengers movie created the vibranium body for himself to begin with, and after the events of Sokovia, there is no reason to think that SWORD didn't procure an Ultron body or two.
From this they could have restored the AI's consciousness and eventually transferred it into Vision as was his original plan. Without the Mind Stone it may have been impossible to bring Vision back, but his body could still work as a vehicle for Ultron.
After all, though White Vision was seen, he wasn't heard, which leaves the door open for the shock of hearing James Spader's bone-chilling voice as the two robots square up together. Vision literally destroyed Ultron last time they met, but this time would be completely different.
Furthering this theory is the fact that White Vision isn't actually pure white in the MCU, there was an unmistakable blue hue to the character. This could potentially be reflective of Ultron's appearance when he first overtook and 'killed' JARVIS before he even took a physical form.