One might say be carefull what you wish for, because the answer was infact Oblivion. Cheeky spoiler by the author amirite?

Yep, after all it's a but presumptuous to think that things like events that are unaccounted by fate can be done by the person who is "fated". Fate clearly has a plan for him, and I doubt cassie is enough to change that plan, in all likelihood this is something he would have done regardless. Let's also not forget the message left behind by mad Prince, "be carefull what you wish for" and the "key to the estuary" where "the answer is oblivion". I have a feeling his wish will end up being something connected to oblivion.

I agree that she remembers all of the revolutions, the hole is probably used as a suicide method at the end of an unsucsesfull revolution after she leaves the book detailing the events behind, I'm also assuming the room somehow keeps its contents throughout the revolutions. let's not forget that the plagues are given names representing their defilement in some sort of way like "soul stealer" or "dread lord". since the name given to Cassies defiled version is "torment" it could maybe mean she is tormented by the knowledge of the past, or the future or something like that.

Sunny in every recent chapter regarding anything :