I got a recruitment option for a mercenary commander for 9 gold. Not sure if that variation and low cost was intended.

Sotha Sill has 5 spell schools one at level 3 and the other at level 9 very fun to watch, not sure if you wanted to make the equivalent of several level spell casters in one unit for the price of 700 sacrifices.

Cool sprites.

I intend to fix the low commander, cost I thought I fixed it before uploading. I also plan on altering the Tribunal god stats later on. Later down the pipeline I plan on adding Dagoth Ur as a playable faction and more of the Great Houses. Due to scheduling conflicts it will be a week or more before each update.

Im going to miss the 40 fiend summons and machinegun meteors. Dagoth Ur! Spooky.

If balance is a priority, which it may not be:
For reference, the Senator's highest tier ritual gives him two level 3 spell schools.
Demonogist could get access to Abaddon, Asmodeus, Belphegor, Buer, Geryon and Orcus all of them have two level 3 magic schools.
Same for the Great Archon and a few others.
The Warlocks highest elemental summon first come with magic items that grant +1 to their spell levels. So they have a single spell school but at level 4.
A demilich gets two Necromancer spell schools.