Estorium is a jungle kingdom south of the Inner Sea. Having long been abandoned after a war against the illithids, it has recently been reclaimed by the sorceress-queen Vyrellis, who seeks to restore it to its former glory. Estorium has a particular focus on magic users of all kinds.
Estorium was a predominantly human empire that stretched across much of the southern continent. Seven hundred years ago, their empire was devastated by a surprise attack by the mind flayer empire of the underdark. Unable to achieve victory against the mind flayers' powerful psionic powers, Estorium's mages studied the mind flayers and ultimately created living psionic constructs called shardminds. With the help of the shardminds, they were eventually able to turn the tide and defeat the mind flayers. Unfortunately, their own once-grand empire lay in ruins; it was estimated that perhaps only ten percent of the population survived. The mages knew that the mind flayers would someday return, and so they placed the shardminds into hibernation until such a time as they were needed once more. They also created artifacts that could grant psionic abilities to the surface races, who lacked such powers. Most of the survivors then sailed north, across the sea, and settled in the towns and cities untouched by the war.
Eventually, one of the psionic artifacts came into the possession of a young boy named Priam Adenis. Though he initially lacked control without anyone to teach him to wield his abilities, he has since mastered his powers and started a school to train others with psionic gifts.
More recently, the shardminds have begun waking up, and more and more individuals have begun to display psionic powers. Could the return of the mind flayers be close at hand?
Before the fall of Estorium, the primary religion in the empire was the worship of Boccob. Other deities with the magic domain, such as Wee Jas and Nalindra, were also common, and evidence has been found for the existence of at least one cult dedicated to Vecna. While non-magic deities were occasionally worshiped, none had strong followings or dedicated temples.
All but the most dedicated of adventurers avoid Estorium; most who venture within are never seen again. Nevertheless, those who have returned have told of the creatures who make these ancient ruins their home. Apart from the typically opportunistic goblinoids that are found in nearly all parts of the world, there have been confirmed sightings of abberations such as grell, large natural beasts, and a few scattered reports of wyverns. There are also rumors that some cities have become inhabited by orium dragons, though these have not been confirmed.
The people of Estorium spoke Ancient Estorian, a language now known almost exclusively by scholars and shardminds.