Shadow Moses Incident
In 2005, during the Shadow Moses Incident, Fox (as the first Cyborg Ninja) infiltrated the island in search of Solid Snake, who was on a mission to neutralize the now-renegade FOXHOUND unit led by Liquid Snake. However, he also ended up letting the Sons of Big Boss know of his existance by killing three of their men while cloaked shortly before Snake infiltrated Shadow Moses Island, resulting in the security detail becoming even tighter.[8] He first made contact with Snake after releasing ArmsTech President Kenneth Baker from captivity and attacking Revolver Ocelot, severing his right hand. Later, after taking out a large group of Genome Soldiers, Fox confronted Snake once again in the laboratory of Hal Emmerich, demanding that they fight to the death. At first, Snake did not recognize the man in the exoskeleton, but after engaging him in hand-to-hand combat, Snake realized who he was. After a time, Snake began to prevail in the battle but before its ultimate conclusion was reached, Fox cried out in pain and fled the laboratory. Fox later helped Snake in his mission by transmitting anonymous messages regarding dangers to Snake under the alias of "Deepthroat" (much like he did during Operation Intrude F014).
When Snake was drawn into battle with Metal Gear REX, Gray Fox managed to damage it further by attacking REX's radome, interfering with the sealed cockpit's sensory input. As Liquid fought to locate Fox and Snake with REX's damaged sensors, Fox revealed to Snake that many years ago, he had been the one who had killed Naomi's parents in Rhodesia but he was unable to bring himself to kill Naomi, who had been too young at the time to remember the incident. Fox begged Snake to tell her the truth. Following this exchange, Fox leapt from his hiding spot and again attacked Metal Gear REX, eventually destroying the radome completely, and forcing Liquid to open the cockpit. This made the tank vulnerable to well placed stinger missiles.
During a second assault on REX, Fox was severely injured when one of his arms was sliced off by the tank's laser. He was then pinned against a wall by REX before being released to fall to the ground. During this time, he managed to completely overwhelm the radome, declaring that "a cornered fox is more dangerous than a jackal!" Fox ordered Snake to fire the stinger, but Liquid informed Snake that if he tried, then Fox would die from the resulting explosion. As Snake hesitated, Fox told him about how after Zanzibar Land, he was recovered on site and was neither truly alive nor truly dead, and that he could finally die in peace with Snake to witness it. As Fox lay on the hanger floor, Liquid tried to kill off Fox once and for all by crushing him under one of Metal Gear's massive feet, however, Fox's grafted exoskeleton meant that this first attempt failed. With REX's second stomp however, the only man to ever achieve the "Fox" codename was no more. His last words were directed towards Snake,
"We're not tools of the government or anyone else. Fighting was the only thing... the only thing I was good at, but... at least I always fought for what I believed in. Snake... farewell..."
— Gray Fox
After escaping the Shadow Moses facility, Snake contacted Naomi, informing her that Fox's last message had been that he would always love her. Snake decided not to tell her that Fox had killed her parents because he was the only family Naomi had ever known. Four years later, Solid Snake referenced Gray Fox's last words to Raiden when explaining why he was motivated to commit grassroots resistance.
