Maybe the humans are just not fighting the daimon units correctly.
either way, the over powered units aren't the main point.
The main source of frustration is the sense of stagnation in this 'final' part of the invasion.
There isnt much happening anymore expect the occasional annoying attacks that set us back having to TO the same regions again.
Interesting things start to develop among human realms and the daimons ruin it by a couple of hit and runs.
