Shadowbane War

The Shadowbane War was a conflict waged between Netheril and the Zhentarim in the. It ended in victory for the Netherese, who broke the Zhentarim's power in the Moonsea region and caused a schism between the Zhentarim and the Church of Bane.

Location
The war took place across the western Moonsea, where the Zhentarim had built their influence.

Causes
Shortly following the Return of the Nertherese city of Thultanthar to Toril in the, the shadovar began a campaign to exterminate their ancient enemies, the phaerimm. By 1383 DR, they had determined that Fzoul Chembryl, the leader of the Zhentarim, had secretly formed an alliance with the phaerimm, and so decided to move against him and the Moonsea cities under Zhentarim control.

Battles
The Netherese successfully razed both Zhentil Keep and the Citadel of the Raven, the two biggest centers of Zhentarim power in the Moonsea. The siege of Zhentil Keep left Fzoul Chembryl dead, and the city's ruins became shrouded in unnatural darkness and choked with undead. Meanwhile, the Zhents fought back viciously, and a Prince of Shade was slain singlehandedly by Cvaal Daoran, the Zhentarim ruler of Phlan.

Aftermath
Following their defeats, the Zhentarim went from controlling half of the Moonsea to having no meaningful foothold in the region, and they ceased to be a threat to the surrounding areas&mdash;such as the Dalelands&mdash;as they had once been. They retreated to their strongholds at Darkhold and Stormwatch.

The death of Fzoul also had profound consequences as it led to a schism within the Zhentarim. Followers of Bane were forced out by followers of Cyric, who would go on to attempt to exert control over the Black Network (although they would prove to be less successful than the Banites had been under Fzoul).

The victorious Netherese attempted to claim the cities of the Moonsea as colonies, however they were stymied when Coronal Ilsevele of Myth Drannor allied with the cities of Hillsfar, Melvaunt, and Thentia to oppose them. Over the next century, Netheril and Myth Drannor would vie for influence over the Moonsea region.