At the end of the Clone Wars five years ago, Chancellor Palpatine founded the Galactic Empire. Equipped with fleets of star destroyers and armies of Stormtroopers, the Empire has seized control of the galaxy and rules with a heavy hand from Coruscant.
The Imperial Navy is the space warfare branch of the Imperial Military. Specific responsibilities of the Imperial Navy include defending Imperial citizens from space-based threats such as pirates, smugglers, and other armed governments, enforcing Imperial will, and overseeing commerce through customs and blockade operations. The Imperial Navy also performs orbital bombardments, transports major ground force deployments, and supports them with space and aerial support.
The Imperial Army is the ground-based branch of the Imperial Military with the primary responsibility of prosecution of ground-side military operations as well as performing other operations such as reconnaissance, pilot ground vehicles, and frontal assaults. Army units are often reinforced by stormtroopers, although the command structure for the two organizations remain separate. On garrisoned worlds, the Army operates in conjunction with Imperial Navy, stormtroopers, and the local constabulary to maintain order and security.
The Stormtrooper Corps is an independent military branch that operates alongside the Army and Navy under their own command structure answering to the Supreme Commander. Many Stormtroopers are Jango Fett clones from the Clone Wars, but new 'volunteers' are starting to fill their ranks. The Corps is predominantly human with the occasional Near-Human.
Lead by Darth Vader, this branch of the Empire is also known as the Inquisitorious.