Zero

Major Zero, briefly known as Major Tom, later simply called Zero, was born in Exeter, England on August 12th, 1909, and was previously in the SAS. Zero was the commander of the CIA Special Forces unit FOX in the 1960's. By the time of Operation Snake Eater, he lived in Portsmouth, New Hampshire, which is also the location of the Pease AFB. Sometime before the Operation, he suffered from gout, but was cured just before. Zero has a prominent scar over his left eye. He also has a sister, and is a huge fan of the James Bond films. He later became the founding member of the Patriots, arguably making him the main antagonist of the entire Metal Gear series.

Biography
Before creating the CIA Special Forces unit FOX, he previously served with the British S.A.S. (where he met The Boss) and with MI6, where he was codenamed "O", from which the codename "Zero" is derived. In 1962, Zero helped Sokolov and his family defect from the Soviet Union to America. He later served as the commanding officer for the Virtuous Mission, the objective to rescue Sokolov from where he was being held.

See Operation Snake Eater

Following the failure of the Virtuous Mission, Zero again became Snake's commanding officer for Operation Snake Eater, with Para-medic and Sigint providing rear support. The mission was a success; the Shagohod was destroyed. The Boss was eliminated, and America recovered a roll of microfilm revealing the location of the Philosophers' Legacy. Upon returning home, Naked Snake earned the title Big Boss.

See San Hieronymo Takeover

Zero's stature rose and his influence grew inside the halls of Langley. In 1970, he conspired with Gene to grab the remainder of the Philosophers' Legacy by staging the uprising on the San Hieronymo Peninsula and stealing Metal Gear. But the plot failed due to Gene's intransigence and the exploits of Naked Snake. Revolver Ocelot succeeded in assassinating the director of the CIA, but was unable to obtain the entire Philosopher's Legacy.

Having lost Gene, Zero joined with Revolver Ocelot, Sigint, Para-medic, EVA and Big Boss to form the Patriots, using the Philosophers' Legacy as a source of funding and Big Boss as a charismatic icon. They hoped to carry out The Boss' vision of unifying the world by controlling information. As a result of Big Boss growing weary of the Patriots' activity, in 1972, they launched the "Les Enfants Terrible" Project, a plan to replicate Big Boss. The project succeeded in producing the three clones, but Big Boss himself condemned the project and parted ways with Zero. Having lost his icon, Zero went into hiding and began to rely on an AI to control the Patriots. By the 21st century, Zero had entrusted management of the Patriots' funds to the neuro-AI, JD.

See Naked Sin

However, Revolver Ocelot, EVA and Naomi Hunter terminated JD as a plan to bring Big Boss back to life, using Solid Snake and Sunny's virus to do so. Once JD was destroyed, the newly revived Big Boss was able to find out the location of Zero. Zero, now only kept alive by life support equipment, was finally killed when Big Boss pulled the plug.

Trivia

 * Major Zero's real name is never mentioned in the MGS series. It's only mentioned in the Metal Gear Database
 * According to Sigint in a radio conversation, Major Zero believes that he was once abducted by a UFO.