Fox hound is an American special force unit founded by Big Boss in 1971 in the metal gear solid series. Specialized in infiltration operations, Fox Hound unit intervenes during the most sensitive operations in which the political situation is in crisis.

This unit recruits mercenaries or young people particularly talented. Its members are exceptional soldiers whithspecial techniques for each one (sniper, heavy weapons...)
A the beginning most famous members of the Fox Hound unit include Naked Snake, Major Zero, Para-Medic and Sigint.

Under the command of Big Boss, agents were Solid Snake, Roy Campbell and Gray Fox. But after the death of Big Boss, Roy Campbell takes the lead and the unit will be thus composed of him, Master Miller and Georges Kesller.

In the last years, Liquid Snake is the new boss and threatens the White House by a nuclear shot if the leftover of Big Boss, biggest soldier of the twentieth century and a billion dollar is not given.

Homeland security minister, Roy Campbell, former commandant of Fox Hound comes back from retirement and asks Solid Snake, to help him save hostages and stop the nuclear threat. Among this new team are Revoler Ocelot, Psycho Mantis, Sniper Wolf, Vulcan Raven and Decoy Octopus.