The collision throws the bell off course, the tether snaps and catches the wizard, so he's fine back in the Present, don't worry, and the bell lands in the Past before the End of Magic.

I'm thinking of a JRPG type setting with a demon lord threatening the world, only there's no Hero, so the increasingly desperate non-demons end up setting off something that kills magic to try and stop the demon lord.

Enter the Time Diver (AKA player). You're not a Hero, but the demon army is set up to conquer