Peace Walker (Basilisk)

Peace Walker, also known as Basilisk, Aurealis, Butterfly, and AL-Aurelia 8000, was an AI weapon developed by Huey Emmerich (who based the design partly on Soviet blueprints of a bipedal locomotive weapon) and Strangelove.

Information
Although technically bipedal, Peace walker's primary mode of transportation is more similar to a quadrupedal machine. It was controlled by two AIs: the Reptile Pod and the Mammal Pod, modeled after the human cerebellum and cerebrum respectively. The mammal pod was deliberately more advanced than the Reptile Pod in order to give it the capacity to launch a retalitory nuclear strike if it verified the strike as an imminate threat. 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, unlike the Metal Gears, was completely incapable of launching a nuclear weapon by itself, only launching out of self defense, as part of the theory of deterrance. 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 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.

Peace Walker Incident
Main Article

Coldman commissioned the creation of Peace Walker (originally designated "Basilisk," and known to the Central American locals as "el basilisco") in order to fulfill his vision of the perfect deterrant. He recruited Huey Emmerich for creating the frame for Peace Walker and Strangelove for creating the Mammal Pod AI. However, Huey eventually found out that Coldman had an entirely different view of nuclear deterrance, as he wanted to test the deterrant with a live nuke to ensure that it was perfect, and refused to participate any longer in its development.

While the weapons systems and the frame itself were complete, the Mammal AI was still undergoing construction as there was apparently a missing piece of The Boss's AI that they needed to ensure that it would be the perfect deterrant. The Peace Sentinels captured Big Boss when the latter broke in to stop the AI, as well as ask The Boss's AI if she had any regrets for her final mission. Strangelove eventually deduced the missing piece required for the AI to function perfectly from torturing Big Boss (ironically through Big Boss not succumbing from the torture), so Coldman reveals 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 does battle with the bipedal form of Peace Walker, doing some damage to Peace Walker. 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 D towards the Nicaraguan/Costa Rican border to a United States Missile Base, with Big Boss riding The Boss's horse chasing after it. Peace Walker was able to make it to its destination, where it will launch its nuclear strike through false data after Strangelove inputted 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 Vladimir was stopped by, ironically enough, Amanda Valenciano Libre's FSLN group and arrested by the Militaires Sans Frontieres, Coldman, dying from a losing a large dose of blood from Vladimir's earlier gunshot, activated Peace Walker, causing not only Peace Walker to launch a "retalitory" nuclear strike towards Cuba, but also transmitted the 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.

However, even after Big Boss managed to destroy Peace Walker, rendering it unable to launch a nuclear strike against Cuba, 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 cores from the Mammal Pod (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). Miller 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

 * Peace Walker is the only AI Weapon to have two AIs (the Reptile and Mammal Pods).
 * The Reptile Pod's designation was AL-Aurelia 8000, an early concept of the AL AI.
 * 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 launch verification code, during its attempt to launch a nuclear strike into Cuba, was "1976."
 * Peace Walker first fought Big Boss in its two-legged 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.

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.