Lavok's Sphere, also known as the Planar Sphere and referred to almost exclusively by that moniker, is a massive and wondrous piece of arcane engineering that appears in Baldur's Gate II: Shadows of Amn.
Lavok's Sphere as it appears after 'phasing' into the surrounding structures
The Planar Sphere is a magic-crafted fortress, possibly a self-contained Demiplane, which is also capable of planeshifting at will to other places throughout the multiverse. It is even capable of travelling to other worlds scattered across the Prime Material, even those that are normally "sealed" against incursions, like Athas and Krynn. It derives this power from an arcane engine that apparently consumes the hearts of Outsiders as fuel; it is unknown if it requires Tanari'ri hearts specifically, or if other Outsiders, such as Baatezu, Eladrin and Aasimon, can also serve as fuel.
Created centuries ago by the wizard Lavok, for whatever reason, the Planar Sphere has recently reappeared in Faerûn, manifesting in the Slums District of Athkatla. The Cowled Wizards have been unable to breach its exterior, but divination have revealed that the blood of a descendant of Lavok would open the Sphere and allow access.
Related quests
- The Hunt for Valygar Corthala
- Inside the Planar Sphere
- Mage Stronghold - Stronghold quest for mages and sorcerers
As a stronghold
Once the Planar Sphere has returned to Athkatla, the Cowled Wizards are willing to grant ownership of it to Gorion's Ward if they are a Mage, or Sorcerer - providing they currently have no other stronghold and are willing to prove responsible (read: "toe the line"). This begins the Mage Stronghold.