It will be difficult for the Mage against the Necromancer because the Necromancer has Banshee’s Wail, and Dead Raising plays a significant role in this battle. However, Chaos magic is good against Necropolis – it deals a lot of damage to undead. But I think that when playing against a Necromancer, the Mage will also need Light magic to strengthen armor and increase attack. After all, the Mage has more knowledge and, consequently, more mana than the Necromancer, which means he can wear him down. + Divine Retribution will help deal with the undead, but there is one BUT: the Necromancer may have Spirit Link, and then he will wear down the Mage!