I think this is nearing it’s final configuration, but I would love any input!
Firebrand of Murlynd (Divine / Combat)
Prerequisites: Exotic Weapon: Firearms, Must worship Murlynd or have gained his special favor
Benefit: Gunpowder and smokepowder weapons work normally for this character while on the planet Oerth in Greyspace. If not on Oerth but in a place where such weapons do not normally work this feat only has that effect if Murlynd has influence there. In all other circumstances where such weapons work, besides Oerth, the character gets +2 to hit.
Normal: Due to the edict of the Gods gunpowder and smokepowder weapons do not work once you have entered the atmosphere of Oerth.