Weapon Immunities

Because of their affiliation with dark and terrible powers, certain necromancers lose their ability to be harmed by mundane weapons. Such wizards, when less than 12th level of experience, can only be harmed by magical weapons or slashing or thrusting weapons of cold iron or silver. Necromancers of 13th level or greater with this ability can only be harmed by magical weapons of +1 or greater enchantment.