What did you expect by launching all-out rigorous wars of attrition and maximizing military efforts by drafting tens of thousands of men?
Besides, NPCs appear by discovery or by formal foundation and action for or against nations.
Also if this helps you in future decisions, the part of the world pictured is what could be recognized as the first world. When the eighth player nation joins, the rest of the world will be open to colonization. This rest of the world, also, is less civilized, so getting control of it will be easier.
Additionally, since these nations are so slapped together out of the blue, one might expect less-than-standard military organization, however, since they exist in the first world, and technology that is good, but not superior to already organized nations.
The three confederations begin to mobilize men toward the front, beginning with simple infantry and some cannons. The Noaste Navy begins patrolling its waters in order to safeguard port towns.