[I’m replying on behalf of u/RetroBeetle Theory he figured out so I send most of the credit of Cassidy and William to him and his post so go check his post out before you read this post if you get confused on mine.] Cassidy and Afton are golden Freddy?What if Cassidy had his father William in purgatory. Where is this purgatory being placed at? Inside the trapped hellhole Cassidy had been in for so many years. UNC takes place inside golden Freddy. This explains why when you death coin him he attacks you. This explains the old man consequence telling Cassidy leave the devil to do his work and not you. William is trapped now like you (Cassidy) were…or so we thought. Which then brings us to HW and SB. William found a way to message others from in side the suite through the log book. IDK how he did it but now it’s starting to makes since. OMG this was the thing that should have been left forgotten. THE LOG BOOK WAS THE THING. I thing I figured the box out from FNAF 4. If you recall from the end of the game it says perhaps some things should be left forgotten. Maybe we were the one (Mike) who locked away the log book. He knew the truth of where William went and knew he was communicating from the book. So he locked it away saying it should be forgotten and locked away as he did with the box. The plot of F4 was from 87 but the end of the game puts you in the time when mike hid away the only thing William was communicating with, the logbook, and the way he escaped was when the vr producers found the box and got ahold of everything which then released Afton from the purgatory he was in.