Metal Gear Solid: Peace Walker/Characters

Snake
Snake is a world-renowned soldier and infiltrator. Formerly affiliated with the CIA's FOX unit, Snake is now a mercenary commander with a following of fanatically-loyal soldiers organized into the unit Militaires Sans Frontieres (MSF). In the 1960s, he was sent into Soviet territory to assassinate his mentor The Boss, averting global thermonuclear war. After the completion of this "Operation Snake Eater" and saving the world, Snake became known among soldiers and mercenaries in the West and East as "Big Boss."

Hot Coldman
Coldman is the CIA Station Chief in Latin America, shunted there from Langley after a falling out with the DCI. He personally oversees the development of the Peace Walker Project in a laboratory in Costa Rica. He is responsible for the operations of the armed group, the Peace Sentinel, in Costa Rica. He believes nuclear deterrence is based on the flawed logic that human beings would not necessarily retaliate against a nuclear strike and will go to any length to prove his theory. By all appearances, Coldman is the story's antagonist.

The Boss
The Boss was Snake's mentor and most beloved. She was known among soldiers all over the world as the "Mother of Special Forces." She and her supernatural team of soldiers known as the Cobra Unit led the Allies to victory in World War II. Her defection to the Soviet Union forced the CIA to send Snake to assassinate her in order to avert global thermonuclear war. Despite being dead for a decade, The Boss casts an immense shadow over the characters and events of this game.

Cipher
A clandestine organization of clandestine organizations, Cipher represents the real power behind the events of this game. They reveal themselves during the final mission as their agents try to steal Metal Gear ZEKE and force Big Boss and his MSF under their control.