The master necromancers are physically frail yet dangerous because of thier necromantic arts, but unlike apprentices they don't have to rely only on that. If you try to approach any master necromancer, they will likely [[teleport]] away and either blast you with lightning or summon more skeletons to make your life miserable. Therefore you should not only be prepared to deal with the undead, but have a source of electricity resistance prepared as well. Also note that the crystal skulls found in master necromancers' inventories are the only way how to get one, apart from [[Scroll of Change Material|transmuting]] a normal [[bone ]] skull into a [[:Category:Light Crystal|light crystal]].