Vita I was talking about that invasion where monsters undead and daimons all had their own realm.
The concept of having ' invasive' new powers that battle each other makes the players decisions more interesting in terms of game theory.
Doesn't have to be daimons, undead or monsters, perhaps something more neutral would work better.
Daimons undead and monsters are so obviously evil that working with them will always be considered bad, people will be very reluctant to do so.
Anyone who manages not joining a side can beat his chest in pride, claiming to be the only ones not corrupted.