If it's a granted resistance, something Eru has gifted to everyone in his universe, then that's what it is. Something granted, specific to the people of that universe (if it's something intrinsic to the universe itself, rather than Eru saying 'no, that shit doesn't fly with my people'), and not to others.
Put another way, some god in some other universe decides that everyone in his universe is immune to bullets. One guy in that universe has invented a gun. He tries to shoot people. It doesn't work out so well because everyone in that universe is immune to bullets.
Do we then grant anyone he faces with that pistol in Khazan the same immunity?