[quote=@GreenGoat]
If multiverse logic is disabled, does this mean mages from certain universes cannot use their own magic?
[/quote]

No. It just means you cannot apply what is "accepted" in your universe as fact. We base abilities and powers off of description alone and not hidden mechanics from another canon. This is to avoid the typical "my magic vs your not magic" arguments in the discord we had in the tournament. The argument usually entails one party claiming whatever their character perceives to be magic and having an ability to nullifying all magic. That means that as long as they think you use magic, even if you technically don't, they could negate anything you do because where they come from it is classified as magic. 

You can still come in with your character and use their version of magic. It just won't have a universal application as described above because of stacking, negation, immunity, and the godmodding rules involved.