As far as I know there is no necromancy "skill" in the latest version nor any Lichdom.
At the character create menu you get the option to be a Necromancer as your first career choice and if you pick the undead kingdom as your race then it automatically changes your first career to Necromancy(no matter what choice you made). You can't raise dead as any other race,eg if you try to make a Dark Elf necro, the game auto changes you into a dead dude
I don't know if your Int affects the number/quality of undead you raise, that info should be in here somewhere but i have not looked.