How do you fight Death Underwater?

[Redeyes]

Originally Posted by JonBrave

I can't afford legions of mages to defend provinces against raiders.

In general: you don't need a legion of mages, but the right mage casting the right spells. You should know which provinces the enemy is likely to raid and be able to defend those.

Apparently you were playing a single-player game? It might just be worth it to put a couple of aboleths or giboleths at the front line, as many as you need to turn away a couple of undead units.