Necromactic Staff (3.5e Equipment)
From D&D Wiki
Necromantic Staffs come from a forest that has been desecrated for over 100 years making the materials hard to find. They give +2 to all DCs of the spells cast by the wielder that come from the necromancy school or the Necromancer class. They are rare so buying one of the town merchant is nearly impossible (especially if hes good). You would have to buy it from an evil person that sells them but they will probably only have 2-5 of them because of there hard to come by materials.