What I've found is that by the time you spend all the spell points required for all this ^^ stuff, you don't have a lot left over for, say, Zombies + spawnpoint + equipment + standard utility spells (Dissolves, Dispels, Nullify, Block, Force Push, etc) - especially with each Poison Gas Cloud costing your Necromancer 4 sbp's. Malcoda + Ghoul Rot + Idol of Pestilence (with Deathlock or Poisoned Blood) serves me well and is less dependent on keeping the enemy mage/creatures stationary, and they're all in-school.