The Rival Orc Tribes & their Great Battles (NWN)

One portal opened by Mulhorand's rebellious wizards led to a world populated by savage orcs. These orcs used the portal to invade Faerûn, overunning many northern settlements and slaying thousands. The manifestations of the god-kings of both Mulhorand and Unther battled the orcs, and the orcs retaliated by summoning divine avatars of their own deities. During these conflicts, known as the Orcgate Wars, the orc god Gruumsh slew the Mulhorandi sun god Re, the first known deicide in the Realms. Many of the Untheric deities were slain as well. The human deities eventually prevailed and the orcs were slain or driven northward.

The deities Set and Osiris battled to succeed Re, and Set murdered his rival. Horus absorbed the divine power of Re and became Horus-Re, defeated Set, and cast the evil god into the desert. Isis resurrected Osiris. All of the Mulhorandi pantheon but Set united in support of Horus-Re. The two old nations paused to rebuild their power and lick their wounds. During this time the empires of Raumathar and Narfell rose in the battlefield territories to the north. In Unther, their chief god Enlil abdicated in favour of his son Gilgeam and vanished, and Istar, the only other surviving Untheric deity, gave the power of her manifestation to Isis and vanished as well. Gilgeam began his 2,000-year declined into despotic tyranny as the ruler of Unther.