I had an expensive spell I could have used against Markgrafdom given their low morale, but didn’t have the opportunity : Myterious Lights. When cast, all units make an easy morale check and if they fail, disappear immediately from the battlefield (considered as retreated). It was my plan to use it to fend them off in case they tried to stop me.

I had another expensive spell to gem burn armies and use lance charges twice (or more). This spell restarts the battle from scratch, with whatever is left in both armies. Pretty deadly. Never had the time to use it.

Also another spell for assassination : just sends a commander to the Void, or Inferno or Kokytos. Quite difficult to use (need high Luck scales in the target province, and the target province must be where the commander is at the end of the turn), I never really tried to use it, but could have come in handy to hurt armies wandering in my lands, or against ennemies with luck scales (like Diamedulla).

There’s also the Wicked Hex alt 5 spell. I could have used it a lot, but in my tests it appeared that it made ennemy armies stronger, tranforming weak units into elephants … I believe executor will fix this and limit the transformation to size 3 animals.