Officer I: "Bunch of goddamn fascist pigs is what they are."
Officer II: "Yeh? Those fascist pigs jus' saved your Human arse."
―Two Artemis rebels, on the UNSC Defense Force
The United Nations Space Command Defense Force (UNSC-DF), colloquially known as UNSC armed forces, is the primary military and law enforcement force of the UN Space Command. It comprises four uniformed branches (the Army, Navy, Marine Corps, and Air Force) as well as two other major commands (SpecWar and Naval Intelligence), in addition to numerous lesser subgroups.
Established during the Interplanetary War of the 2160s, the UNSC Defense Force and its massive supply of troops and capitol to tactically overwhelm hostile guerrillas and conventional forces. During the war's latter months and the years following, the UNSC-DF quickly grew into Humanity's superior military: by 2185, there were more than 25 million active duty personnel and another 70 million organized into various reserve organizations. This number continued to rise steadily until the late twenty-fifth and twenty-sixth centuries (specifically due to the events of the Insurrection of 2490 and the First Great War), at which point the Defense Force's size boomed exponentially, numbering in the tens of billions by 2530.