Defenses
The only entrance to the tower could be blocked off during a siege, isolating the structure from the rest of the castle.
Structure
The Great Keep had its own armory, water supply, and food stores. The first floor was dedicated to sleeping quarters for the shig'harakhi. The second floor contained a lavish study and library where flame mages researched their spells. The entire third floor was an armory filled with weapons for the fanatics. The top floor of the Great Keep was an astronomical observatory complete with star charts and a telescope enchanted with true seeing.