[Kuritza]

Once again, I am almost positive that stealth is resolved before global spells. At least my SCs were teleporting into empty province - shadow vestals lead by a druid were gone. All you need is to scrpit them 'hide' instead of attacking another adjacent province.
As for the 'useless in late game' - thank GOD they dont dominate all battelfields in the lategame as well. Its not like Ermor doesnt have free undead from neutral priests, decent national troops and nice mages after all.
But does it make shadow vestals obsolete?... find a province with druids and you have got stealthy raiders. Or in my current game shadow vestals scripted for 'wait and attack large enemies' are making my flying mammoth obsolete. F9W9 shadow vestals make a very short work of mammoths.