Force Operations X (FOX) is a United States special forces unit established under the auspices of the CIA in 1964 during the events of Metal Gear Solid 3: Snake Eater. The brainchild of Major Zero and legendary World War II hero The Boss, FOX was created to perform top-secret operations pertinent to the security of the US and its allies while avoiding the political ramifications inherent to open warfare. The unit was heavily modeled after the British Army's SAS and the United States Army's "Green Berets" Special Forces. FOX was composed of hand-picked, highly-trained operatives equipped with some of the most advanced weapons and gear available to the US military, as well as several experimental devices that never saw widespread usage. Though FOX simultaneously operated as both a combat unit and a covert intelligence outfit, the group primarily specialized in one-man infiltration missions where stealth was paramount to achieving critical mission objectives, and its success allowed FOX to serve as the template for all future US special forces units. Like its direct successor FOXHOUND, several later members of FOX would eventually go rogue, leading Zero to disband the unit in 1970 following the events of Metal Gear Solid: Portable Ops.
Kojima Productions, the main studio responsible for development of the Metal Gear Solid series, also uses the distinctive yellow FOX emblem as their company logo. Hideo Kojima's second development studio Kojima Productions Los Angeles features a red version of the FOX emblem as their logo.
Virtuous Mission & Operation Snake Eater
One of the foremost reasons behind FOX's creation was to recover a defecting Soviet rocket scientist named Nikolai Sokolov. Although Sokolov's family successfully crossed the Iron Curtain in late 1962, Sokolov himself was handed back over to Soviet agents only a few weeks later as part of a secret deal between then-US President John F. Kennedy and USSR Premier Nikita Khrushchev; this was the real reason behind the end of the Cuban Missile Crisis. Major Zero personally conducted the original CIA operation enabling Sokolov and his family to defect, escorting Nikolai as far as West Berlin before receiving new orders only a week later to return the scientist to Soviet custody.
Zero's "Virtuous Mission" to recover Sokolov nearly two years later was intended to be the proving grounds for FOX before being officially organized as a special forces unit. To execute this mission, FOX's first field agent Naked Snake was dispatched to Tselinoyarsk (translated as the "Virgin Cliffs"), a largely-uninhabited region in the southern Soviet Union where Sokolov was forced to continue his weapons development research on the Shagohod. After insertion via HALO jump, Snake quickly contacted Sokolov and attempted to extract him, learning additional information about the Shagohod's true purpose as a long-range nuclear delivery system in the process. Unfortunately, Snake was betrayed by The Boss, who had joined the Virtuous Mission's support team before suddenly defecting to the USSR and recapturing Sokolov with the help of her old Cobra Unit. Volgin, an ambitious GRU colonel and The Boss' new Soviet ally, proceeded to fire one of his newly-acquired "Davy Crockett" portable recoilless nuclear launchers on Russian soil, provoking an international incident between the US and the Soviet Union. Snake managed to survive this betrayal, though he faced intense interrogation afterward by US military top brass with accusations of aiding The Boss' defection.
Following the complete failure of the Virtuous Mission, the future of FOX and its personnel was called into serious question by the CIA. However, a telephone conversation between President Lyndon Johnson and Khrushchev inadvertently created an opportunity for FOX's redemption: to prevent nuclear war, Khrushchev demanded that the US clean up its mess by eliminating both The Boss and Volgin. As The Boss' only "disciple," Snake was the primary candidate for this new mission; together the pair had even developed a new form of hand-to-hand fighting known as CQC, or Close Quarters Combat. After a week spent recuperating, Naked Snake was once again sent to Tselinoyarsk to commence "Operation Snake Eater" with remote support from FOX members Zero, Para-Medic and Sigint.
Despite being repeatedly ambushed by both The Boss and her Cobra Unit during Operation Snake Eater, Snake eliminated each of the Cobras in turn before reaching Volgin's mountain fortress of Groznyj Grad with field support from a Russian double agent code-named EVA. Although Snake successfully infiltrated the base's weapons hangar containing both the Shagohod and Sokolov, he was severely beaten by an enraged Volgin and imprisoned; Sokolov was purportedly killed by Volgin a short time later (this was retconned in MGS: Portable Ops with the explanation that Sokolov had earlier ingested a Fake Death Pill). After losing his right eye to Major Ocelot's Single Action Army revolver during a torture session conducted by Volgin, Snake escaped his cell and contacted EVA, who had already recovered Snake's confiscated weapons and equipment.
Snake and EVA went on to destroy the Shagohod as it was being piloted by Volgin; Volgin himself was killed by a chance lightning bolt following his lengthy battle against Snake. The Boss, Snake's last objective, was waiting near EVA's prepared "WiG" ground effect vehicle in anticipation of their final encounter. She attempted to explain the philosophical reasons behind her supposed defection to the USSR, but The Boss dutifully avoided revealing her true mission to obtain the "Philosophers' Legacy," an enormous military slush fund totaling approximately one hundred billion US dollars, from Volgin on behalf of the United States. Snake reluctantly fought and killed his former mentor before returning to the US as a hero, where he was awarded the new rank of "Big Boss" by President Johnson.
Thanks to Snake's outstanding efforts, FOX became recognized as an official CIA special forces unit following Operation Snake Eater. Snake also learned the truth behind The Boss' "defection" from an audio recording left by EVA, who revealed herself to be a Chinese triple agent after absconding with the microfilm supposedly containing details regarding how to obtain the Philosophers' Legacy. In reality, EVA had been given a fake microfilm; Ocelot secretly obtained the authentic Legacy (later discovered to only grant access to half of the Legacy's total funds) before turning the microfilm over to the CIA Director and confirming his own double agent status as ADAM, Snake's second intended GRU contact. Disillusioned by his own government's callous exploitation of The Boss for the sake of recovering the Legacy, Big Boss resigned from FOX after Operation Snake Eater, with Zero retiring shortly afterwards.