Against which factions is it easier for demons to fight, and against which is it more difficult?

Here, there is one hero among the Orcs: Garuna. It is quite possible that her choice is very justified against demons, especially if not too many demons are summoned from the gates (on the way to the main demon forces, you can gain rage and increase the attack of the summoned creatures). On the other hand, the counter-hero is Nimue. Demons are sometimes summoned even more often than the main squad, and it is not so easy to increase the attack.