AI weapon (Peace Walker Project)

The AI weapons were unmanned combat vehicles developed by the rogue CIA Peace Sentinels in the early 1970s, as part of the Peace Walker Project. The AI units had various tech abilities such as high speed, mobility, or destructive power.

Development
Under the directive of CIA Station Chief Hot Coldman, the Peace Sentinels successfully developed four types of AI weapon. Codenamed Pupa, Chrysalis, Cocoon, and Peace Walker, they reflected hovercraft, flying, treaded, and walking type vehicles, respectively. Each was equipped with at least one AI pod containing the artificial intelligence that operated the vehicle's frame. Each also had a speech synthesis system, for relaying verbal communication on the battlefield to surrounding forces.

The AI weapons' main development was headed by Huey Emmerich, while Strangelove created Peace Walker's advanced decision-making AI system, known as the Mammal Pod. Peace Walker was the final culmination of AI research gathered during the development of Pupa, Chysalis and Cocoon. As such, the names given to the three prototypes all referred to the transformation stage of a butterfly's life cycle, while Peace Walker itself was often referred to as "Butterfly," and its Mammal Pod, the "Imago."

In 1974, Big Boss (Naked Snake) and the Militaires Sans Frontieres encountered each of these machines while attempting to investigate the Peace Sentinels' presence in Costa Rica, who were also transporting nuclear weapons into the country. After dealing enough damage to each weapon, and gaining access to the interior of their respective AI pods, Big Boss and MSF ripped out the memory boards of the AI itself, in order to disable it. After being tampered with by the MSF, the AI pods of the Pupa, Chrysalis, and Cocoon, weapons detached themselves from the main frames, and launched themselves on an escape vector, using their built-in rocket boosters.

After the events of the mission, the MSF used the parts and memory boards they had salvaged from the AI weapons to create Metal Gear ZEKE.

List of AI weapons

 * Pupa
 * GW-Pupa 5000
 * Chrysalis
 * TJ-Chrysalis 6000
 * Cocoon
 * TR-Cocoon 7000
 * Peace Walker
 * AL-Aurelia 8000 (Reptile Pod)
 * BS-Imago (Mammal Pod)

Trivia
The AIs belonging to the AI weapons for the Peace Walker project's speech synthesis system repeated pre-set messages that would play depending on the situation. Peace Walker was the only one of the AI weapons from this project, as well as the AI weapons overall (counting ZEKE) that was capable of self-generated speech.

Behind the scenes
After completing Metal Gear Solid: Peace Walker, Extra Ops allows the player to fight upgraded versions of the AI weapons. Other than their harder difficulty, the Type II models sound somewhat more human, while the Custom models are painted almost completely red and make human-like threats during battle.