NHF – new heroes for Heroes V 3.1.

I would try 5.5, but as I know, it's not compatible with NHF, and I don't want to play without your mod. There's a catch everywhere.

Added 1 minute ago
With the vanilla AI, you can only play against Orcs, because it doesn't cast a single dodge spell. Thanks to their blood, they might provide resistance. Other factions have terrible AI.