Solid Snake (real name David, commonly referred to as Snake, and later referred to as Old Snake) was a former spy, special operations soldier, and mercenary. He was a product of the Les Infants Terrible project and "son" of legendary soldier Big Boss, along with his "brothers" Liquid Snake and Solidus Snake.
Possessing an IQ of 180 and fluent in six languages, he was known as "the man who makes the impossible possible" and his exploits made him into a living legend among the military black ops. Initially a Green Beret, Snake was later inducted into High-Tech Special Forces Unit FOXHOUND in the mid 1990s while it was under the leadership of Big Boss. Repeatedly tasked with disarming and destroying the latest incarnation of Metal Gear, a bipedal nuclear weapon-armed tank, Snake would thrice avert potential nuclear catastrophe, becoming a famed war hero.
Following the Shadow Moses Incident of 2005 and subsequent smear campaign by the Patriots, the secret organization behind American politics, Snake was labelled a terrorist. He faked his own death in the Tanker Incident of 2007, though he re-emerged two years later to assist Raiden in the Big Shell Incident. During this time, his cells entered a state of accelerated aging, causing his health to decline. The cause of his rapid aging was explained by Naomi Hunter, who examined Snake and determined that it was caused by planned genetic changes during the cloning process.
In 2014, Snake performed his final mission, during which he defeated Liquid Ocelot and destroyed the Patriots. After one last encounter with Big Boss, Snake chose to live his remaining days in peace.