Big Boss is the main antagonist of the NES version of Metal Gear and Snake's Revenge. He serves as the main antagonist, last boss of the first game, penultimate of the second and is the central enemy of Solid Snake. While he vaguely resembles his original counterpart, this version of him is much worse, lacking any of the sympathetic qualities of the former.
Metal Gear (NES)
Big Boss was Solid Snake's commander, and sent him on a mission to infiltrate Outer Heaven, providing advice along the way. However, he secretly intended for Snake to bring back misinformation to the East and West and fail in his mission, due to him being the real leader of Outer Heaven. However, he underestimated Snake and after the Supercomputer controlling the Metal Gear was destroyed, he confronted Snake in the soon to self-destruct facility, admitting his role in Outer Heaven, in a grueling battle before seemingly perishing at Snake's hands.
Metal Gear: Snake's Revenge
In Snake's Revenge, it was revealed that Big Boss survived, but needed to be rebuilt as a cyborg, and was left vengeful against his former soldier. Three years later, Big Boss took control of an enemy base, continuing mass production of various Metal Gear 1s, which he also had shipped to various belligerent countries against the United States, and built a new Metal Gear, Metal Gear 2, and put nuclear weapons on it to launch at several major locations, including Washington, Paris, and Tokyo.
After imprisoning the mole Jennifer, Big Boss killed a soldier under Snake's command, Nick Myer, who nonetheless deduced that Big Boss could not leave his command room without risking death.Eventually confronting Snake once again, Big Boss challenged him to a final battle. After a few hits, Big Boss transformed his mechanical pieces into a gargantuan metal figure, which he gloated that had no weak points. However, this is shown to be false as Snake lured him from his command room and put mines below him to blow his mecha body and killing him for real.