there could be warlords and mutants on the battlefield.
Mutants would use more GDI style weaponry mixed with their own style, warlords more like nod.
These could be in a camp, somewhere on the map. they would work like tech buildings except.. if you get units to the camp you can bribe them to join your side- then from this camp you can train Mutant/Warlord units for cheap.
The problem is, they are not always loyal, if someone else bribes them back all the warlord/ Mutant units on the map will come under their control.
Even ones that were formerly yours! they need to be defended.