The Necromancy skill on The Iron Wolf is a custom skill which yields great potential and support for any mage or warrior to be.
Necromancy is only avilable to the Soulless race, and cannot be used or learned by any other race.
As a Soulless you start with a Necromancer scepter and a Necromancer skill of 40.0. Once you enter the world the souls of the dead will random be attracted to you like moths to a flame, and once they find you, they will join you.
So in other words: What fuels Necromancer magic are souls, theese souls are passively gained. The zones and areas you are in effects the number of souls that seek you out, Graveyards for example has a higher passive gain than the plains and forests. So where dead resides, souls are a plenty.
Once you use your Necromancer scepter on a corpse you (currently) have the choise between 5 Necromancer spells. Three summons, one polymorph and lastly a resurrection gate.
All Necromancer spells come with a duration and a successrate, both the duration and the successrate increase with your Necromancy skill and your intelligence. All skills cost souls to cast, the souls you collect pasively (there is no way to actively increase the soul-yield, except residing in areas with much dead, like graveyards)
If you have souls enough there is no limit to the number of summons you can have, as well as you can be polymorphed and have a resgate handy, all at the same time. This makes the Necromancer skill more than just a support skill, but rather an overall gamechanger and a good pick for the solo player.