Colonel Volgin from Metal Gear Solid 3 is a sadist who, within minutes of appearing, fires a Davy Crocket nuke at his countrymen just to give it "a test drive," knowing full well that he won't be blamed for it, even when one of his subordinates is clinging to his arm, begging him not to. Then come one of the most vicious Cold-Blooded Torture scenes in video games. Note that it's damn clear he didn't care if the torturee lives or dies before getting the proper information, as long as he gets his kicks. Then we also have the fact that Volgin, long before the events of the game, had participated in the Katyn Forest Massacre as a NKVD member, where he managed to kill over 20,000 Polish officers with his bare hands, and not only that, but he also removed their blindfolds before beating them to a pulp, and he killed several people in both the Hungarian Revolution and the East Germany Uprising, which he not only had absolutely no regrets about killing 100,000 anti-communist activists, but even boasted about the feat.
If it turns out that artificial intelligence in this setting can act on its own volition, the Patriot AIs are more monsterous than the founders themselves.. To give you a rundown on the history of them, the A Is were created by Zero after he basically lost faith in humanity to govern the Patriots after Zero's eventual death. However, the Patriots A Is instigated the Big Shell Incident as well as the Tanker Incident in an attempt to garner control over humanity by manipulating information by conducting the S3 Plan. It was also heavily implied that they also used Dolph's marine corps to create RAY and then take it back after they no longer served a use to them (Ocelot, during the Tanker chapter, tells Dolph, and later, Gurlukovich, that he actually intends to take RAY back to the Patriots), and had not only framed Jackson for embezzling funds, but also framed Dead Cell with several terrorist activities that resulted in the deaths of countless civilians and military personnel alike. What's worse is that they kidnapped Olga's newborn kid, and placed her kid's life on the line, blackmailing Olga into even going as far as to kill her own unit (something that she did not take well at all, as she valued them as not only friends but also her own family), and later they even did the exact same thing to Rosemary before the fight with Solidus in order to threaten Raiden into killing Solidus. What's even worse with Rosemary is that she was also pregnant with Raiden's child at the time, meaning that not only were they threating her life, but also their child's existance. They also heavily implied just before Raiden kills Solidus that they basically viewed humanity as nothing more than tools and weapons to discard later on when they no longer serve a use. They also were responsible for the creation of the War Economy, which nearly tore apart the entire world as a result. The kicker? They apparently did all this without Zero's knowledge or consent, and even eliminated any trace of the Boss's last will, even loyalty, her most treasured belief.
If Nastasha Romanenko's novel, In the Darkness of Shadow Moses: The Unofficial Truth, as well as various hints in Metal Gear Solid, are anything to go by, they (at least in terms of the A Is) also may have had a hand in manipulating portions of the Shadow Moses Incident, even if it ultimately went out of their control, such as creating Metal Gear REX and the later attempted recovery of it, Solid Snake being injected with FOXDIE to kill off both FOXHOUND and those in the know about the REX project in order to retrieve both REX and the Genome Soldiers, and also forced Roy Campbell in participating in the mission with the threat of Meryl and himself being killed (even going as far as to deliberately send Meryl to Shadow Moses on the same day that FOXHOUND would rebel just to get the message clear to Campbell about their threat). They also intended for Snake to die in the mission with FOXDIE, yet Naomi's desire for revenge by editing the FOXDIE program to have a wildcard value ironically ruined that part of the plan.
If you think about it, Volgin's "test-drive" (and probably Coldman's involvement in getting Volgin into doing his "test-drive", caused pretty much everything that happens in the Metal Gear Solid series. That's quite an accomplishment.
Although the Metal Gear Ac!d series isn't canon to the main series, even it has some pretty horrific people. Metal Gear Ac!d 2 has a complete monster, and surprise, it isn't Dr. Koppelthorn, since he did have a legitimate excuse for what he did (as his wife was killed and wanted to bring her back). No, the real complete monster was Wiseman. He instigated a horrific event known as the Praulia Massacre as the Model 2s did not provide satisfactory data in his eyes, and sent in the Model 3s to be cleaned up. He was also responsible for the death of Koppelthorne's wife, which also resulted in the events of what happened later on. Finally, after gaining the Lucindia File, he had Venus execute Snake simply because he outlived his usefulness. Speaking of Snake, he also had Venus render him amnesiac in the first place. Although he ultimately was arrested by the FBI for war crimes, his reaction in the ending suggests that he will end up escaping custody in some way or another.
