Necromancy if ever implimented should be kept apart from the magic system..
for instance a necromancer should b more vulnerable than mages in health and other attributes..
as in the attribute level needed for learning necromancy should be the highest..
or else it would be like one player playing with two characters at the same time...
a necromancer must be forced to use his minions and other spells to guard him from death. to make it balanced.
imbuing weapons with Poison and such negatives effects could be given to him as part of crafting like potion making to Alchemy..
simple pets (loyal or harming) could be bound to other characters by necro mancy
Just a few ideas..