In Metal Gear Solid: Peace Walker, the nuclear-capable bipedal weapon built by the Peace Sentinels is Peace Walker.
Peace Walker is an autonomous weapons platform developed in Costa Rica by the Peace Sentinels. Its design combines nuclear capability with artificial intelligence, allowing it to operate without relying entirely on a human pilot. The project is connected to Cold War deterrence and the idea that an automated weapon could guarantee retaliation after a nuclear attack.
Big Boss and the Militaires Sans Frontières become involved after investigating unusual military activity in Central America. The machine’s name reflects the game’s recurring tension between peace as a political promise and peace enforced through overwhelming military power.
Metal Gear ZEKE is a separate weapon constructed later by the player’s private army. The Shagohod belongs to the earlier events of Metal Gear Solid 3, while Metal Gear RAY appears in a different generation of the series. These names are easy to mix up because each refers to a major mechanized weapon, but Peace Walker is both the project’s name and the game’s central machine.