The Guardian Units of Nations, often abbreviated as GUN or G.U.N., is a group in the Sonic the Hedgehog series. It is a worldwide military and law enforcement organization. Run by a man only known as the Commander, G.U.N. seeks to protect the earth from all sorts of threats, including Dr. Eggman and the Black Arms.
G.U.N. has vast resources, including an army of soldiers and peacekeepers, fighter planes and other instruments of warfare. While G.U.N. receives orders from the President of the United Federation, it operates under the sole discretion of the Commander, who has been known to use G.U.N.'s resources to bring down enemies.