The wizards of the Closed Circle studied the lore of the Dragon Below and the daelkyr, and in 641 YK the combined forces of the Church of the Silver Flame, the Esoteric Order of Aureon, and the Guild of Starlight and Shadow destroyed the order.
There is one dark stain in the shared history of the arcane orders. Three hundred years ago, a third order arose in Sharn—a sinister cabal called the Closed Circle. This order specialized in transmutation and necromancy and dabbled in the forbidden lore of the daelkyr and the Dragon Below. It’s said that the members of the Closed Circle went mad and sought to summon terrible things; whatever the truth, the guild was wiped out more than two hundred years ago by the combined action of the Church of the Silver Flame, the Esoteric Order, and the Guild of Starlight and Shadows. Hidden workshops of the Closed Circle might still be found in Sharn, where vengeful liches or other wizards of the Circle practice their dark arts in hiding.
The In the early days of Galifar, three wizards' circles took shape in the southern kingdom: the Esoteric Order of Aureon, the Guild of Starlight and Shadows, and the Closed Circle. The wizards of the Closed Circle specialized in transmutation, conjuration, and necromancy, and they sought to unlock the secrets of the daelkyr and the Qabalrin, as well as the power of the Dragon Below. In 641 YK, the Closed Circle was obliterated by the combined force of the Church of the Silver Flame and its two rival circles. But its workshops and mageholds, filled with dark and deadly secrets, may still be hidden across Breland or Darguun.
Erandis d'Vol has thousands of years of tradition to draw upon. So how is it that the ruins of the Closed Circle -- an order that only lasted a few centuries -- can have anything to offer her? The fact that Erandis is drawing upon tradition can serve as an anchor when it comes to innovation. The humans of the Closed Circle were unorthodox and inventive, and their merging of daelkyr techniques with necromancy is an excellent explanation of phenomena such as the Mother Cyst feat and its related spells. So if you want to stage a race to keep the Blood of Vol from gaining new necromantic techniques, you don't have to send adventurers to Xen'drik -- the darkness could be hidden beneath Sharn, in the ruined fortress of the Closed Circle.