Okay, I've just discovered something new. Something that has been here for a long time. However, a lot of people ignored it, including myself. There were some theories about it, but none of them had strong evidence.
The Purple Guy, the five missing children, the haunted animatronics; All of them were meant to happen, because of it. Mike, Jeremy and Fritz were involved in it and Phone Guy was the killer. They tried to prevent it, but it was too late.
Scott Cawthon has finally shown us the truth in Five Nights at Freddy's 3. If you brighten one respective image, it will be there. Here it is:
I feel so bad.