Thayd

Thayd was a wizard who led a rebellion against Mulhorand and Unther in.

History
Thayd led a rebellion against Mulhorand and Unther in. He briefly seized the northern provinces of both empires.

Thayd's goal was to overthrow both empires, and take their territories as part of his own Overempire to achieve limitless dominion over the Realms. In response to his rebellion, Mulhorandi arcane magic was placed under strict control by the god-kings, creating a bureaucracy of priests to keep watch over its developments, thus creating the power structures of Mulhorand that endured well into.

In, Thayd and his conspirators were defeated. Before his execution, he prophesized that Mulhorand and Unther would decline. He ensured that would be so by opening a portal to a savage world dominated by warmongering orcs on the same year, before his capture and execution for inciting fellow wizards to rebellion: after his death, no one in Faerun knew of the portal. The orcs on the other world discovered the portals several years later, and used them for the invasions that would later become the Orcgate Wars. Together, both events orchestrated by the archmage Thayd managed to end the Great Age of the Mulhorandi Empire.

The magocracy of Thay was named after Thayd, honoring him for his rebellion against Mulhorand two thousand years before and prophesizing the Empire's eventual decline.

Rumors & Legends
Thayd was known as the Last Surviving Apprentice of the Imaskari.

According to the Book of Ratep, Thayd had studied the lore of the Great Enemy Enslavers (the Imaskari) and made it available to his followers. The Pharaoh believed that this lore had corrupted the magician, who would enslave the Mulan once more if left unchecked.

Per some sources, he let in hordes of orcs that would fight the Empires with a curse, rather than a portal.

Some sources suggest that Thayd may have endured beyond his death as an undead sentience attaching itself to the living to control them, destroying his host within the space of a few weeks.