"That's the problem with mixing magic between universes. The rules are different everywhere - and generally speaking, your own magic will be weaker away from your home universe. Sometimes you'll lose access to it entirely, depending on where it's sourced. As for your permanent flags... there are millions of magic systems that Beorin has access to that are just as immutable, and with enough fenangling they could probably find a way to work around yours in a matter of hours. When unstoppable forces meet immovable objects, it's however you design the terrain that determines what ultimately comes out on top."
Ayia crossed her arms over his chest. "If I had to guess, they don't have anything at their immediate disposal to directly counteract your Tempest. The best-case scenario for us is that they stop your domain from spreading after awhile, but the worst is that they can compress it down somewhat. Either way you'll probably still have access to your powers, but they'll be significantly more limited than they would be on your homeworld."