Crown of Karsus

The Crown of Karsus is an ancient and powerful artifact in the Forgotten Realms, crafted by the briefly divine Netherese arcanist Karsus, that lets its wearer wield magical power while remaining independent of the Weave. Karsus wore it when he tried to supplant Mystryl as the god of magic, an act known as Karsus's Folly that ended the empire of Netheril and partially destroyed the crown, which the archdevil Mephistopheles later kept in his vault for over a millennium. In Baldur's Gate III, Enver Gortash and the Dark Urge steal it from Mephistopheles and place it atop the elder brain beneath Moonrise Towers, controlling the Netherbrain through the three netherstones sundered from the crown.