The Sphere of Defense of the Empire, alternatively referred to as the Ministry of Defense or the Pyramid of Defense, represented one of the twelve Spheres of Influence within the re-established Sith Empire. Governed by a Dark Council member, this Sphere was responsible for supervising the Imperial Military's role in protecting the Empire, collaboratively managing the military alongside the Spheres of Military Offense and Military Strategy. During the Great Galactic War and the subsequent Cold War against the Galactic Republic, Darth Marr presided over this Sphere.
Following the Empire's loss to the Eternal Empire, Empress Darth Acina merged this sphere with the Spheres of Military Offense and Military Strategy, creating the unified Sphere of Military Command.