I recently came up with a weird theory for twisted wonderland, I put it up on my tumblr. But here it is:
What of the monster we had to face at the beginning was Grim but like a failed timeline...
Let me explain, the surroundings look pretty messed up in that match so what if to stop him and get the students to work together, Crowley summoned mc/yuu. Then, after it worked, as you can't continue the game until you do beat it, he decided to turn back time to the beginning of the school year, so as to stop both it and the events leading up to it.
That could be why he is constantly dodging the idea of sending yuu home, cause he sees having yuu here will help make the timeline run smoothly.
The factor that no body outside of the school knows about the overblots could help the theory. After all you would need to be pretty powerful and in a high position to keep the news from getting out. After all overblots are seen as rare. Crowley is headmaster and we have yet to see him truly let loose magically.
Crowley could be shoving duties, overblots and the events leading to them, onto yuu because he knows he can't stop them. He might already tried and failed(the failed timeline and whose to say that was the only one). So he pushes it to yuu because he truly believes that only they can tame the students and stop the events in their tracks.
He would have gotten a bit of evidence with the failed timeline but might have wanted to test yuu to make sure it wasn't a fluke or one time thing, the mine incident.
Plus with the turning back time he, Crowley, might have needed to erase yuu's memories. It could be why we don't hear about yuu's world very much because while doing so Crowley would have been exhausted, with the whole turning back time, and might have accidentally erased more than he meant to. So, yuu might not remember much of their world.
This idea has been festering in my mind so enjoy, have a lovely day. #I_hate_my_brain_sometimes #twisted_wondeland