Illithid War
From Syra D&D Wiki
The Illithid War was a massive conflict approximately seven hundred years ago that began when the illithid empire attacked Estorium. Though they achieved a number of major early victories, they were ultimately defeated when Estorian wizards created the shardminds, allowing them to use the illithids' psionic powers against them.
Estorium was almost completely destroyed in the war, and most of the survivors left to either the northern continent or the Pharis desert to the south. Though few records survived detailing the extent of the damage to the mind flayer empire, no more than the occasional lone illithid has been sighted in the centuries since.
