Spirits where thought of as just servants to the necromancer something in most cases to use, and discard. If they had a act, or errand they prefer to not perform themselves they would call upon the dead to carry out there wishes. If they required forbidden knowledge again it was the spirits who where summoned to feed there hunger for the knowledge they desired. Tracking down a lost item, or hidden treasure again it was a spirit of the dead who was called to do the necromancers bidding.
It is no wonder that some necromancers would request there body be destroyed upon there death. Being that they where prime targets for new, and uprising practitioners of the art to call upon, and be forced back into there former body to serve. After all who better to seek wisdom from than a person who has had so much contact with the dead, and gained so much forbidden knowledge in there human lives.
