[quote=@Treue]
I do agree with [@Grnmachine]'s point on magic. Many games have different lore as to how magic is used, and where the energy comes from. In Guilty Gear for example, magic is an infinite resource from the dimension know as the Backyard, and is channeled through who or whatever is attempting to use it. That said, using magic does take a toll, more akin to physical exhaustion however.
[/quote]

In that particular case any magic user from Guilty Gear would be unable to use magic outside the Guilty Gear section of the game world as the Backyard dimension isn't connected to the rest of gaming reality. That might change as I'm still sorting out how each of the different gaming realities interact and crossover from one another.

As I said I've presented a general rule on magic but it is of course subject to change based on which game a mage happens to be coming from and what the source of magic is in their particular reality.