Swordplay... What is the state of projectile weapons in this world? Does the world have an omnipresent utility fog that abhors anything moving above a certain speed? (Omnipresent utility fog might already qualify as the basis for magic; there could even be a good epic plotline of someone trying to turn off the anti-gun restrictions.) Is the world covered in engineered bacteria that seek out and consume potential firearm propellants? (i.e., why don’t people carry guns?)