A dark theory of mine

Right now it's looking very likely that the authorities have been harvesting DNA from Jane to make the amplifiers. What if they're not only doing that, but also harvesting her eggs, fertilizing them with the sperm of a powerful donor, and implanting those eggs into surrogate mothers they've kidnapped from low-tier districts.

The authorities could be mass-producing babies with Aura Manipulation that they could indoctrinate and train from birth to create super-soldiers. Imagine hundreds or even thousands of Aura Manipulation users more powerful and better trained than John, all completely loyal to the authorities. I don't think this is actually going to happen in the story as it might be a bit too dark, but I'm sure it's something the authorities could do if they wanted to.