Ermor?

[Endoperez]

As said before, there are many anti-undead spells, items and even units. Using them, superior numbers of undead won't be enough. AI can't use these tactics correctly, and playing Ermor's, Pangaea's or C'tis' undead themes against AI is very easy.

[sushiboat]

Astral mages casting mental attack spells like Paralyze, Mind Burn, Soul Slay, etc., ignore the mindless undead, and those spells have 100 Range and 100 Precision (but MR negates). If you are fighting the Ashen Empire theme, often the only units with minds will be Ghouls and the commanders. If you can kill alll the commanders, the mindless undead will stop fighting and dissolve.