The unknown shore
The old world is loosely ruled by the Litch King and divided in to separate city states that still fight small wars between them. Each city state is limited to an area of no more the 30 square miles. This includes all the farm land that may be administrated by one city state.
The Litch Kings conquest of the land happened several hundred years ago as the result of his frustration with the constant wars of the great empires interrupting his experiments. He raised armies of dead solders and marched on the capitals of the five great nations. Told them to knock that shit off and that he was in charge now.
Then he broke the empires in to city states and told his people not to make him come back here or they will not like what will happen. As a result of this enforced peace the rein of the Litch King has been a time of art since and learning for the old world.
City states are not allowed to form alliances. When one city sate goes to war against its neighbor they must do it alone.