Game Mechanics: Common NPCs have way too much mana

[Nirgon]

Seeing Froglok shamans in seb cast 5-6 envenomed bolts and then heal themselves 10 times is a bit much (or wizards casting 6 ice comets and 3 conflags)...

Source:

I find that one cast of that and one or two casts of Theft of Thought often render a creature completely incapable of spell casting.