Quote Originally Posted by Braininthejar2 View Post
He recovered the lost page of the spellbook by rewinding it to before he even started his training - but he didn't dare to try to bring his dead mentor back: by then he wasn't willing to rewind stuff for anything short of world-saving.
Just a reminder that the lost page of the spellbook was in a sanctum and thus may have different rules of reality than other places on Earth. This may be the case or this may not be the case, it depends entirely on the writers.

What I am saying rules with rewinding time either in how far you go back, or the fact will rewinding time have effects on the rest of reality may be different when the place you are rewinding is a self contained marble that is an anchor in protecting earth from external threats from other dimensions / other planets.