The Treaty of Athena is the agreement that ended the fighting between Kira's Kingdom and both the New Kingdom Alliance and the Japanese uprising during the Year of Rebellion. Signed in early 12 NE by Emperor Gene Smith and the heads-of-state of Cybele, Demeter, Feronia, and Japan the Treaty decentralized the government of Kira's Kingdom by reorganizing it into a federal monarchy, reintegrating the members of the New Kingdom Alliance, and later Japan, as constituent states. The Treaty serves as a loose constitution for Kira's Kingdom, supplementing and in some cases overriding the Imperial Articles.
Under the Treaty of Athena, Kira's Kingdom is divided into several constituent states, which control most of their own domestic and economic affairs. Each state is subordinate to the central Kira's Kingdom government, over which the Emperor retains full control but is advised by the Holy Imperial Council, which is made up by the head of each constituent state or a representative thereof.
The primary military force is controlled by the central government, but each state retains the right to maintain its own small military force for self-defense and domestic security.