Wait, woah, why... What's going on? Why is that Pope guy wanting to rewrite what happened? I don't get it. And why is Sacchan so into helping screw Sensei's mind. I know, that's the point of this new arc, but its so frustrating, I don't like it how he's not with his new buddies anymore. I hate these evil timeloops!
The Pope wanted a pawn he can use, he thought to break off the uncontrollable Sacchan away, but turns out Sensey is even more uncontrollable especially after his experiences in the new world.
So he rewrote the world to keep the two together instead of breaking them apart, that way Sacchan can exert control on Sensey, and the Pope can manipulate her to guide Sensey in whichever way he's actually aiming for.
Another thing that you may note.
The starting priestess is Aria, Annette's successor, even though Tama got reset back to her crisis with the tree monster.
It's almost like she's
'beyond his control'
Annette was also the one whose call broke Sensey out of Sacchan's control before the rewrite.
So I think we'll get Sensey's POV here to show how twisted Sacchan is, but the actual climax of the arc will be Annette vs Sacchan i.e. the future vs the past.