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

I don’t play as demons… but when I was playing through the campaign, it was very difficult… against the forest dwellers… to be honest, I think demons are weak… they have few ranged units… only one unit is actually good, guess which one… and you can’t just use abilities whenever you want…

Added after 2 minutes
Although, maybe I just don’t know how to play as them… I always run out of resources for building and hiring units when I play as demons…