The War of Unification is a war which happened before the start of the Unified Era. Before the continent was known as Imperia, the realms of Athos, Elyria, Thena, Certes and the realm of the Vestra were working together to unite the land. The war finally ended, Imperia was formed and the Unified Era began.
Near the end of the war, the followers of Aios and the people of the Vestra began to create Masters from Vessels who would ultimately unite the Gods and Goddesses. When this failed, however, the Vestra sealed away the Masters. In the year 2 of the Unified Era the King of Elyria took away the land of the Vestra because of this, and since then they have been travelling merchants.