The Greatwall castle itself is a three level fortified tower accessed via two gated courtyards. The main outer gate leads to the Greatwall Encampment which is a palisaded encampment outside the entrance to the castle. Both lie on high ground on the northeastern side of the nortwestern part of the Barta Crags region of Gransys.
Access to the Greatwall castle is given by permission of the Duke. The Duke will allow the Arisen access to put down a hostile takeover of the castle by the cultist group Salvation during the quest Deny Salvation.