Gray Fox

In 1995, Gray Fox was the agent assigned to Operation Intrude N312. Fox's objective was to gather data on a top-secret nuclear weapon that the fortified state of Outer Heaven was secretly developing. Several days later, Fox was captured by enemy forces and the last message he transmitted to headquarters were the words "Metal Gear..." In the follow-up mission, known as Operation Intrude N313, Fox was rescued by newly-recruited FOXHOUND member, Solid Snake and Fox provided Snake with all the known facts about Metal Gear; a nuclear-equipped walking battle tank. Together, they successfully destroyed the Metal Gear prototype under development in Outer Heaven.

However, shortly after the destruction of Metal Gear, it was revealed that Big Boss himself was secretly the commander of Outer Heaven's forces all along. Sometime after the destruction of Outer Heaven, Fox deserted the FOXHOUND unit and disappeared along with Big Boss (who was presumed dead after his battle with Snake). Around this time, Fox followed him and helped in the formation of Zanzibar Land by becoming an active participant of the "War of Mercenaries". After his success in the war, he was assigned as commander of Zanzibar Land's Mercenary Force, also known as the "Dogs of War."