Paz is another Metal Gear character who, despite her relatively short time in the saga, is still very pivotal. She’s also-chronologically-the very first Metal Gear pilot (although there’s one in Metal Gear Solid Portable ops, that continuity is disputed) in the series.
Paz in introduced to both Big Boss and Kaz Miler in Costa Rica, where she is apparently a student of the “university of peace” along with Professor Galvez (Who is in reality a KGB agent). She appears to be a person who is a pacifist. Big Boss is initially reluctant to help, but then he hears a tape recording that she obtained from her ‘friend’ Cecile Cosmidades, capturing the voice of the Boss AI pod, making Big Boss wonder if “The Boss” faked her death. Paz and “Galvez”‘s mission helps to build Big Boss’s small mercenary unit into the massive Militaries San Frontieras, building toward’s his dream of a nation for soldiers: Outer Heaven. It also, arguably, begins his downfall from a well-intentioned hero into a darker character.
During Snake’s missions during the Peace Walker incident, she helps him with information on Costa Rica, such as the local flora and fauna.
Eventually though, she is captured by Peace Sentinel and their leader Hot Coldman, and Galvez’s true loyalties and intentions (as Russian agent Zadarnov) are revealed. When Big Boss reaches her, he falls into an ambush by Zadarnov and Coldman
Thankfully, MSF arrives in the nick of time, bailing Big Boss out and rescuing Paz. Paz then moves to mother base. However, Zardarnov is able to escape multiple times, and both Big Boss and Kaz begin to notice problems with Paz’s initial story; Cecille, for instance, did not know her prior to Mother Base.
All is revealed shortly after Big Boss is forced to kill Zadarnov. Big Boss’s Metal Gear ZEKE-which was intended to be controlled by an AI-rises unexpectedly from it’s launch bay, with Paz inside.
Turns out Paz-real name Pacificia Ocean-is a CIPHER agent, trained by Big Boss’s former mission commander Major Zero-CIPHER’s leader-to pose as a student to gain Big Boss’s sympathy.
She gives Big Boss an ultimatum-rejoin CIPHER or she will use Metal Gear ZEKE to launch a nuke at the United states, framing MSF. Big Boss refuses, and takes down the Metal Gear. Paz falls into the ocean.
However, Paz is eventually recovered by XOF, a division of CIPHER led by Skull Face, and taken to Camp Omega. However, Skull face has plans of his own, intending to take down both Big Boss and Zero. He tortures Paz for that information, but also booby-traps her as well with two explosive devices. Big Boss goes to camp omega to rescue Paz (and ally Chico as well, who attempted his own ill-fated rescue). He’s able to extract her aboard the helicopter and flee the camp. One of the devices is removed by the helicopter medic. Meanwhile, XOF destroys Mother Base while all this is going on, and after the base is destroyed, things are about to get worse-there’s a second device implanted that they weren’t able to find.
Paz sacrifices herself by jumping out of the helicopter, but the resulting explosion not only kills Paz, but puts Big Boss and the medic into a coma, and kills Chico and the helicopter pilot Morpho.
Nine years later, the medic-now transformed by mental suggestion and plastic surgery into Big Boss’s double Venom Snake-discovers Paz in the medical platform on his own Mother Base. It appears she somehow miraculously survived, although she has no knowledge of her true identity, and thinks she is just her student persona and knows nothing of CIPHER. Venom attempts to jog her memory by recovering some missing MSF soldiers and giving her photos.
However, it’s revealed the whole thing is an elaborate hallucination, caused by the medic/Venom’s grief over not being able to save her, as well as the damage suffered in the explosion. As the hallucination’s fade, a flock of Morpho butterflies appear to Venom, reminding him of her one last time.
Despite her treachery and uncertain loyalties, Paz still remains a mascot of sorts for Mother Base, appearing in signage and weird “idol” posters around the base.
Oh yeah, and she even has her own music video that you can unlock in Peace Walker-the song “Love Deterrence.”