Undead/Demon prophets

[MaxWilson]

As an aside, I've heard conjecture that Crystal Shield + Crystal Matrix makes Slave Matrix a cheap version of Ring of Wizardry through the Communion effect. I've never tried it, but it might come in handy if you're trying to cast high-path army buffs like Bone Grinding. You have enough slots on most casters for Skull Staff + Skullface + Ring of Sorcery + Crystal Matrix.

Edit: of course you could just equip the Crystal Shield directly. The advantage would be that you don't have to deal with the encumbrance, which actually makes it better for SCs than for casters now that I think of it. Chayot, for instance.

-Max