Tactic : how to fight undead ?

[Vynd]

If you're up against Ashen Ermor, with skeletons and ghouls and whatnot, then missile weapons are also pretty effective, since most of their troops move slowly and their only ranged attacks are javelins.

If it is Soul Gate Ermor you are fighting this won't be nearly as effective since the arrows will have a hard time damaging their ethereal troops. But any sort of area effect damage spell should be useful, like say Holy Pyre, or perhaps Blade Wind.

But of course you'll want lots and lots of priests no matter what.