Battle of the Gods

The Battle of the Gods was a conflict between the Untheric and Mulhorandi pantheons against the Orc pantheon, as well of one of the major battles in the ongoing Dragonfall War, that took place in -1071 DR as part of the Orcgate Wars.

History
During the Orcgate Wars, the gray orcs and their clerics had developed amazingly powerful and deadly spells; the most potent of magics being their ability to directly call down avatars of their deities. When the orcs invaded Mulhorand and Unther, the gods of those nations also sent their avatars to the lands that later would become Thay, to face the invaders' gods, resulting in what was later known as the Battle of the Gods.

Ill-prepared to defend themselves against the orc gods, however, the gods of Mulhorand and Unther were slaughtered. Re was the first to fall, slain by Gruumsh, with several more powers of the Untheric pantheon following: Inanna was killed by Bahgtru, Girru by Luthic, Nergal by Ilneval, and Nanna-Sin by Shargaas. Ki and Utu were later killed by the orc deities as well. Tiamat, who was also the enemy of the other Untheric gods, saw an opportunity to slay Gilgeam while he was battling Ilneval. However, Marduk (Bahamut's Untheric aspect) intercepted her before she could act and in the ensuing battle they killed each other in one of the climactic battles of the Dragonfall War.

Aftermath
Despite their initial advantage, the orcs and their deities were eventually defeated by the survivors of the Mulhorandi and Untheric pantheons in the final Orcgate war, that took place in -1069 DR.

Gilgeam became the remaining god-king of Unther. In time, he became more and more tyrannical, making the Untherite to turn to the worship of Tiamat for succor and eventually allowing her to return to Toril in her aspect of the Dark Lady.