Founded in the 1960s, XOF was a support unit founded by CIA agent Major Zero to assist FOX, the CIA's unique special forces unit that specialized in infiltration. After Major Zero joined a conspiracy that sought to unify the world under one government, XOF became Zero's personal strike force. In the 1970s, XOF's commander, Skull Face, betrayed Zero and used XOF to further his own goals.
In 1964 during the Cold War, the CIA created Force Operation X, or FOX, a special forces group designed to handle top secret infiltration missions. To support FOX, Major Zero created XOF to support FOX operatives on missions by providing critical intelligence and removing traces to ensure that FOX maintained total secrecy. Once of FOX and XOF's missions, Operation Snake Eater, lead to the death of the Boss, a legendary visionary soldier. The Boss's closest friends and allies, determined to fulfill what they believed was her vision of world peace, formed the Patriots, an organization dedicated to united the world. FOX was disbanded, by Zero recruited XOF into the Patriots.
Skull Face, XOF's commander, hated Zero and despised his plan, believing it would wipe out cultural identities and assimilate all peoples under an American empire. He poisoned Zero, putting him into a coma, and took control of XOF. He made war against Big Boss, a former FOX operative, who he viewed as a threat, and destroyed the base of Big Boss's mercenary army. Then he made preparations for his own vision of world peace, one based on nuclear deterrence and devoid of the English language. However, Big Boss's army returned in the form of a new mercenary group, Diamond Dogs, which wiped out XOF and killed Skull Face, putting an end to his plans.
Battle vs. Mobile Task Force Omega-7 (by Laquearius)