The Sphere of Defense of the Empire, also known as the Ministry of Defense and the Pyramid of Defense, was one of the twelve Spheres of Influence within the reconstituted Sith Empire. Ruled by a member of the Dark Council, the Sphere oversaw the use of the Imperial Military in the defense of the Empire, sharing joint control of the military with the Spheres of Military Offense and Military Strategy. Darth Marr was the head of the Sphere throughout the Great Galactic War and the Cold War with the Galactic Republic.