The Dust
The dust is actually some form of nanomachine, meant to have a symbiotic relationship with humans giving them power in return for creating more nanites. The problem is that something cause the human population to drop below the minimum for the nanites to function. Nobody anticipated this because the world was so populous at the start. As a result it slowly killed people by siphoning off their bodily processes to keep the nanite population stable unaware that it was killing off its creators.The reason most people fall apart if they discover the big secret of the world is that as part of a "Don't skynet me bro" type security feature the nanites aren't supposed to be able to assume human form. Edgar didn't know this which was why his first attempts at making people failed but eventually he discovered an accidental work around of keeping them unaware of what they really are. The few who can resist it have developed mentally enough without being erased that they can subconsciously resist the kill order.
