Solid Snake is a retired mercenary and a former member of the U.S. military branch known as FOXHOUND. Incredibly intelligent, he possesses an I.Q. of 180 and is a master of six languages. He is regarded as a legend, having previously infiltrated Outer Heaven years before and defeating its leader Big Boss, who had been dubbed the greatest soldier who ever lived. He is also well-known for his three defeats over the bipedal, nuclear-armed mechs known as Metal Gear.