Nation in Selene: The Colony of The Frog Mafia, The Republic of Fat Deviantart
Nation Name: The Disputed Territories of Muterra
Plot: Any small island, safely away from most civilised places, where both of the above factions condisered countries in-game can duke it out for supremacy while still being considered distant news stories. If not, some broad plot of land, shaped like a circle, to indicate some sparsely populated, sparsely documented general area where the events take place. EDIT: That island south of the Righteous Empire would be a cool spot to be.
Customisation: The capital for both "countries" (rather, factions that are a cross between political parties and warrior clans) is Blasthole, somewhere in the middle. Other major cities include Mega-Gorod 1 along the coast, as well as Hardcheez and Barterville somewhere farther inland.