The Ocrisian Empire reigned for nearly a thousand years before its fall 900 years before the Plague. The Ocrisians who ruled the empire were a race about which little is now known, but they are generally believed to have been a race of mostly well-preserved undead with purple skin, practically infinite natural lifespans, and emaciated bodies. Unsurprisingly, the Ocrisians were skilled necromancers, and conquered their foes with armies consisting of former foes.
The Ocrisians placed their capitol, Polis Sarn ("the White City"), where the Polis Academia now stands. Other major cities included Atrum Sarn, Rubir Sarn, Anlulan Sarn, and Serseran Sarn - each of which was later made home to one of the Academies of magic - as well as Crusrek, Antriss (from which Antrissa takes its name), Akerek, Avydos, and Cendiss (from which the Cendizan Empire takes its name).
The Ocrisians became fewer and fewer as time went on, and soon new Ocrisians stopped appearing for unknown reasons. The remaining Ocrisians ruled for a time, but eventually perished altogether, and non-Ocrisians began governing the empire. Emboldened by the disappearance of the Ocrisians and their undead armies, the various holdings of the empire began squabbling among themselves and tore the empire to pieces, thus ending the Ocrisian empire.