It means that you would be controlling them. Sort of like how your control your own nation, but slightly less involved. Like... Deciding their actions on a global stage, and internal stage, but only when others mention them. 

For instance, if China wanted to attack Japan, I would PM the NPC-controller of Japan and let them know and they'd tell me how Japan would react and we'd discuss the outcome, but the controller wouldn't directly write from Japan's perspective.