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

Yes, you're probably right (+1). But I'm saying this because I know what Haven is capable of; with skillful play, you can give everyone a hard time.

But what if you play Inferno correctly? Can you sense where the fairness lies! Each faction, whether it's Orcs, Inferno, Haven, or others, can overcome any challenge with the right development.