Skull Face is first and foremost, a horrible person. His full list of crimes would likely be too long and too unpleasant to put here, but with torture, mass murder through parasitic infection and human experimentation among them, there is a reason he's considered one of the worst villains in the entire
Metal Gear series. Unfortunately for everyone, I have no sense of taste and he ended up, for various reasons, my favourite character in the series, and one of my favourite fictional characters in general.
But I'm getting ahead of myself.
Before Skull Face
was Skull Face, he was just a boy. What turned him into Skull Face was a series of events beginning somewhere near the end of the Second World War, with the bombing of a factory in a village in Northern Transylvania. The factory was set alight, flames and scalding oil burning everyone inside. Yet Skull Face survived - kept alive solely through the introduction of parasites to his body, living within him and preventing him from ever truly dying. The fire stripped him of his family, his humanity, his skin's ability to feel, and his own youth.
Hungary has a particularly tumultuous history. Its borders have been constantly redrawn, its lands and people repeatedly divided in terms of place and identity. Skull Face had already lost his physical identity, but the political changes in his country led him to lose essentially all he had left - his cultural identity and his language. For this, he came to resent cultural and linguistic imperialism, not just within Hungary but across the world. Revenge became the sole thing driving him - revenge for the suffering and death of his people, and for his own loss of identity.
He spent the rest of his youth as an assassin within Soviet Hungary, enacting his revenge through espionage and murder of Soviet officials - often using deadly parasites to carry out inconspicuous killings that could be ruled as accidental. Stalin himself was one of his targets.
Some time after this, he defected to the west, ending up in the SAS and meeting with one of the
Metal Gear series' most pivotal figures: Major Zero. From here, Zero developed a considerable amount of trust in him, recruiting him as his XO, taking him with him as he began working for the CIA. When Zero established FOX, a unit created to conduct covert operations where the legendary Big Boss would first earn his reputation, Zero also established XOF, a top secret backup unit, with Skull Face at its head.
Years spent tailing Big Boss in the shadows only added to his resentment, not to mention Zero's pursuit of a plan that would enact loss of language and identity on a global scale - controlling the world through the use of a single language, English. Skull Face recognised English as a deadly, oppressive force, and Zero's intended use of it as something to be stopped at all costs. So in secret, Skull Face plotted against him, using the resources of his organisation - Cipher - given to XOF to begin research into a counterweapon: vocal cord parasites.
The first step of Skull Face's plan was carried out in March 1975, following the capture of failed Cipher agent Pacifica Ocean (posing as the schoolgirl Paz Ortega Andrade) and her imprisonment in Camp Omega. The black site was used by Skull Face and XOF to interrogate her for the whereabouts of Major Zero, who had gone into hiding after splitting with Big Boss over ideology. The imprisonment of the young boy Chico, a friend of "Paz" seeking to rescue her, enabled Skull Face to try and kill two birds with one stone - finding out the locations of both Big Boss, and Zero.
Skull Face first attacked Mother Base directly, using a bomb cruelly inserted into Paz's body to destroy Big Boss' helicopter, sending him and the onboard medic into nine-year comas, injuring and killing the others onboard. One year later, Skull Face successfully struck at Zero with the information given up by Paz, infecting him with a parasite that would slowly kill his mental functions while leaving his body alive. Essentially inheriting all of Cipher's resources, Skull Face spent the rest of these nine years working on producing vocal cord parasites, isolating strains for each language in the world, in addition to carrying out research into nuclear weapons and metallic archaea.
Skull Face's search for Big Boss continued upon learning of his awakening in a hospital in Cyprus, sending XOF to hunt him down, though they failed to eliminate both the real Big Boss (who went into hiding after the escape) or his body double, Venom Snake, who took over the role as Big Boss as a final act of revenge from Zero. During this time, Skull Face had recruited a boy with psychic powers known only as Tretij Rebenok (the third boy) and the reanimated corpse of Colonel Volgin, in addition to having created several units of parasitically-controlled soldiers. The third boy's powers were used to control Metal Gear Sahelanthropus, a bipedal nuclear-equipped mech that Skull Face intended to use as a threat to the world, forcing countries to purchase nuclear weapons supplied (and controlled) exclusively by him.
Skull Face's primary weapon was always the vocal cord parasites, more specifically, the English strain, which would kill anyone who spoke it and transmit endlessly. In his eyes, it was a liberator, to destroy the conquering force that was English, and preserve cultures from being wiped away by an all-powerful lingua franca. Three strains existed, one given to the assassin, Quiet, who was sent to spread it throughout Mother Base, but her bond with Venom Snake prevented her from carrying out her mission. Skull Face revealed the final two strains to Snake as he prepared to reveal the true power of Sahelanthropus to him, but an unforeseen psychic bond between Tretij Rebenok and the vengeful Eli caused the psychic to betray him. Trapped by fire, Skull Face was crushed under metal by Sahelanthropus.
The second of the English parasite strains was destroyed by Venom Snake, the third retrieved by Tretij Rebenok and given to Eli, ultimately being destroyed too. Skull Face was still alive when Venom Snake and Kazuhira Miller found him, the parasites preventing him from dying even as they tore his limbs off with his own rifle. The final blow was dealt by Huey Emmerich, a self-serving scientist who had worked under both Skull Face and Big Boss over the years.
But Skull Face's legacy was not, and perhaps would never be, over. Just as the parasites kept him alive long after his death, his will for revenge lived on. He died accepting the fact that his existence would be scrubbed from the earth, dying still just as insignificant as he was all those years ago, just a boy in a burning factory. But the suffering and anger he had caused others ensured his ideals lived on, the cycle of pain and revenge maintained.
For Skull Face, it ended the same way it began, really. In fire.