Peace Walker (Basilisk)

Peace Walker, also known as Basilisk, was a bipedal nuclear-armed AI weapon developed by Huey Emmerich and Strangelove.

Information
Although capable of bipedal locomotion, Peace Walker's primary mode of transportation was quadrupedal. It also utilized stealth from radar and satellite images, which drastically reduced any chance of it being destroyed in a nuclear attack. Its most devastating weapon, however, was a massive hydrogen bomb mounted to the frame that was more powerful than even the Tsar Bomba, so that if necessary, it could sneak into enemy territory and self destruct.

Peace Walker was controlled by two AIs: the Reptile Pod and the Mammal Pod, which were modeled after the human cerebellum and cerebrum, respectively. While the Reptile Pod was mainly responsible for operating the main frame, the Mammal Pod possessed more advanced decision-making capabilities, giving it the capacity to launch a retaliatory nuclear strike at the most effective target. The Mammal Pod AI's neural processes were modelled after the legendary soldier The Boss.

Unlike Metal Gear, Peace Walker was completely incapable of launching a nuclear weapon by itself, only launching out of self defense, as part of the theory of deterrence. However, it could be tricked into launching a nuclear weapon into a country if supplied with false data, which could depict an imaginary Soviet nuclear attack on the U.S. It could also transmit this false data to third parties, such as NORAD, as revealed by Coldman when he initiated the launch code with his dying breath. Combined with the fact that the data would be transmitted via a spread spectrum multi-length frequency pattern, rendering even electromagnetic pulses ineffective in blocking the signal, this was arguably its most dangerous ability outside of its hydrogen bomb. Aside from the nuclear launcher, Peace Walker included a radiation generator, a pair of flamethrowers, regular missiles, s-mines and mole missiles. All of this weaponry possessed a heavy emphasis towards defense. Also, if someone tried to attack Peace Walker, it would abort its previous command and go into a small threat suppression mode.

History
In 1974, Hot Coldman commissioned the creation of Peace Walker (originally designated as "Basilisk" and known to the Central American locals as "el basilisco") in order to fulfill his vision of the "perfect deterrent." He recruited Huey Emmerich to create the frame for Peace Walker and Strangelove to create the Mammal Pod AI. However, Huey eventually discovered Coldman's intentions to have Peace Walker launch an actual nuclear warhead, to test its decision-making capabilities, and refused to participate any longer in its development.

Though the weapons systems and the frame itself were eventually completed, the Mammal Pod was still undergoing construction, since the AI required another component that would ensure that Peace Walker would be the perfect deterrant. The Peace Sentinels captured Big Boss (Naked Snake) when the latter broke in to destroy the AI, though he was distracted by the AI's imitation of The Boss, and asked whether she had any regrets during her final mission. Strangelove eventually deduced the missing piece required for the AI to function perfectly by torturing Big Boss (ironically through Big Boss not succumbing from the torture), so Coldman revealed the first target for Peace Walker's nuclear launch: Mother Base. Part of the reason dealt with eliminating the Militaires Sans Frontieres, although he also intended to launch it there because the trade winds would scatter the fallout throughout Central America and poison the crops and fish markets, thus allowing for "free hands" to help with the mass production of Peace Walker.

Big Boss later battled the bipedal form of Peace Walker, doing some damage to the weapon. Unfortunately, it wasn't enough to completely incapacitate it. It started malfunctioning as a result of the damage, causing Coldman's Hind D to shoot at the AI pod to get it out of its glitch. It then transformed into it's quadrupedal form and headed with Coldman's Hind towards the Nicaraguan-Costa Rican border to a United States missile base, while Big Boss, astride The Boss's horse, gave pursuit. Peace Walker was able to make it to its destination, where it would launch its nuclear strike through false data after Strangelove input the coordinates.

However, Vladimir Zadornov betrays Coldman and changes the target to Cuba, as it will cause anti-American sentiment to spread internationally, allowing the Soviets to win the Cold War. Coldman was then shot by Vladimir. However, he missed the killing shot deliberately because he still needed the launch code. After Zadonov was stopped by Amanda Valenciano Libre's Sandinistas, and arrested by the Militaires Sans Frontieres, Coldman, dying from blood loss inflicted by Zadornov's earlier gunshot, activated Peace Walker, causing the weapon to not only launch a "retalitory" nuclear strike towards Cuba, but also transmit false data towards various third party organizations, such as NORAD, nearly causing an all out nuclear war. As Coldman died before he could give the abort code (knowing full well that he would die soon when launching it), Big Boss and Strangelove were forced to destroy Peace Walker.

Although Big Boss managed to destroy Peace Walker, rendering it unable to launch a nuclear strike, it was still transmitting false data towards NORAD and the Pentagon, causing a nuclear war to become inevitable. Even Big Boss ripping out the memory boards from the Mammal Pod's AI (which allowed him to get inside to rip the hard drives out due to not being able to forcibly remove the lock due to it being strong enough to withstand a nuclear blast) was not enough to end it, as authority for transmitting the fake data was passed on to the Reptile Pod. Miraculously, however, Peace Walker managed to get up on its own and sacrifice itself to end it by drowning in the lake, causing the data to short out from the circuits being exposed to water.

Afterwards, the Militaires Sans Frontieres returned to Nicaragua to remove the nuclear missile from Peace Walker, in order to avoid another conflict with the natives (the missile was still radioactive and could potentially contaminate the lake, or end up being discovered by terrorists). Kazuhira Miller, MSF's subcommander, then suggested to Big Boss that he place it on Metal Gear ZEKE, otherwise they would need to dispose of it. Although Big Boss hesitated, being taken aback by the suggestion, he ultimately agreed: as long as the world maintained its nuclear weapons, the MSF would need to use nukes themselves as a deterrent.

Trivia

 * The Reptile Pod's designation was AL-Aurelia 8000; the initials are based on those of Abraham Lincoln, while Aurelia is a synonym for "chrysalis." The Mammal Pod's designation was BS-Imago; the initials are based on an abbreviation of "Boss," while Imago is the name given to an insect's final life stage.
 * Peace Walker's former codename of "Basilisk" is a reference to the lizard of the same name, which is able to travel atop any terrain, stand on two legs, and even run across water, similar to Peace Walker's all-terrain capabilities.
 * The name was also a reference to the mythological basilisk, a highly venomous creature that is considered to be the "King of Snakes." A Roman legend told of a knight who once killed a Basilisk with a spear, though he and his horse ended up dying after the venom seeped up the spear. Peace Walker also possessed the ability to petrify enemies (albeit, via an immobilization ray).
 * Peace Walker's head featured the emblem of a butterfly. The machine itself was referred to as such by Big Boss, during a conversation with Huey Emmerich.
 * Peace Walker's launch verification code, during its attempt to launch a nuclear strike into Cuba, was "1976."
 * Peace Walker first fought Big Boss in its bipedal form, while utilizing the Reptile Pod; its movements resembling those of a theropod dinosaur. As it switched to the Mammal Pod, it walked on four legs, much like a quadrupedal mammal.

Behind the scenes
"King of Snakes," another name for the mythological basilisk, was a name used to refer to Naked Snake in advertising for Metal Gear Solid 3.

When Play Arts Kai unveiled its figurines for Metal Gear Solid: Peace Walker, they referred to the Peace Walker figurine as Basilisk.

Gameplay
During the second battle with Peace Walker, the mecha will attempt to prepare the countdown for the nuclear strike into Cuba. If Snake fails to stop the countdown, then a Game Over sequence occurs where the missile is shown being launched.

An Extra Ops mission requires Snake to fight an upgraded version of Peace Walker colored in red paint. The way it is defeated after taking out its HP is similar to how Pupa, Cocoon, and Chrysalis were defeated (its AI pod being released after jumping out of the AI pod, causing it to launch like a rocket). Also, if the player supplies moderate damage to the head, the player can also unlock the Peace Walker head for use on ZEKE.

During the Peace Walker Type II & Peace Walker Custom battles, the Mammal Pod is absent.