Well if you really wanted a fucked up evil faction, you could have a group of Wyld users who do basically suicide attacks on their enemies by sneaking into their capitals or cities and then going berserk, trying to rack up as high a kill count before they get put down.
If they must fight, they will invoke a spirit of the Wyld to possess them and go wild. Druidic monster forms. However, this means they can be slain by blade and spear.