"You asked what about me? It's simple. I love cutting up live people, and I like killing people so much, I can't stand it. I kill; therefore I am! I am who I am. That's all the evidence I need!"
—Barry the Chopper (anime version only), "The Red Glow" (subtitles)
Original manga and Brotherhood:
- Shou Tucker, the Sewing-Life Alchemist, is known for his ability to create chimeras capable of speech. He's introduced to the Elric brothers as an awkward man with a 4-year-old daughter named Nina. With his State Alchemist license soon to expire, Tucker created another Chimera by fusing Nina and her dog Alexander into a miserable Half-Human Hybrid which is in constant agony. When the Elric brothers discovered Nina's new state, Edward's rage nearly drove him to kill Tucker. It is then revealed that the other speaking Chimera was actually his wife and Nina's mother, whom Tucker created by fusing her to another animal, earning him his State Alchemist status in the first place. Tucker refuses to admit what he did was horrible, going as far as to tell the Elric brothers that they shouldn't have a problem with his actions and that anybody else in his position would have done the same thing. While only appearing in one chapter, Shou Tucker manages to be one of the most depraved characters in the manga and Brotherhood anime.
- Father is a being from beyond the Gate given form in a small flask and named Homunculus by the nameless slave who would become van Hohenheim in the Xerxes empire. Desiring to escape the flask, Homunculus would trick the king of Xerxes into a ritual that slaughtered multiple people to initiate an alchemy ritual that killed everyone in Xerxes and split their souls between Hohenheim and Homunculus, to the former's horror. Later founding the nation of Amestris and creating the Homunculi, he took the name of "Father", guiding Amestris to become a military dictatorship that initiated military conflicts to provide bloodshed for an even greater ritual, including the genocide of the Ishvalan people. Intending to kill and steal the souls of tens of millions so that he could devour God, or Truth itself, Father demonstrates cold sadism when he faces Hohenheim and his children again, mentally torturing them as he also abandons or tries to absorb his own Homunculi children. While he sees himself as an existence above humans, this is simply a reflection of Father's arrogance and pride, desiring to ascend ever higher, no matter who or what he has to destroy to gain ultimate knowledge and power.
- The unnamed Doctor with the gold tooth created the homunculus Wrath by inserting Philosopher's Stones into the bodies of thirteen candidates, cackling when the process painfully killed the first twelve. Using the now-mindless bodies of the first dozen candidates, the Doctor unleashes them upon the heroes trying to stop Father from destroying Amestris. To force Mustang to open the Gate of Truth, the Doctor slits the throat of his Love Interest so she will bleed to death unless he opens it to save her. Knowing Father's plan would kill millions, the Doctor only strives to cause as much death as he can.
- The Sacred Star of Milos: "Melvin Voyager", actually Security Chief Atlas, is a power-hungry, sociopathic Cretan soldier, who starts off by denouncing his vows to protect the Crichton family by brutally murdering the female protagonist Julia's parents and then rips the skin of Julia's brother's Ashleigh's face in order to steal his identity. This was done so that Atlas could easily manipulate the rebel group, Bats, into making a transmutation circle for him by promising Creta enough power to rival other nations. Ashleigh, in turn, ended up becoming a vengeful Knight Templar, seeking revenge for Milos after losing his faith for its people. After showing his true colors, Atlas murders Bats' leader, Miranda, so that he can use her blood to activate the circle. He then proceeds to murder his co-conspirator, Raul, as well when it turns out there is not enough sacrificial blood. After succeeding in activating the circle, Atlas sacrifices dozens of Amestrian soldiers by feeding them to Milos's machinery to create a Philosopher's Stone for himself. A textbook sociopath who abandoned his honor and home country for power, Atlas stood out as one of the most vile villains in the Brotherhood canon.
- Dante is a 400-year-old woman who keeps herself alive by trading her soul with a younger person, then killing her old body, repeating the process indefinitely. When Dante's own Philosopher's Stone runs out, she sets in motion a plan to cause so much misery in Amestris that someone will be desperate enough to recreate the Stone, allowing her to steal it with no risk to herself. Abusive towards her Homunculi "children", Dante arranges for Ed to kill Greed. Stealing the body of her assistant, Dante later tries to move into the body of one of Ed's Love Interests when her current body begins to deteriorate. Said action is made even more disgusting by the fact Ed is both a teenager and the son of Dante's own ex-lover. When Gluttony falls into despair because of Lust's death, Dante, annoyed with him being unwilling to follow orders, callously destroys his mind to make him easier to control.
- This version of Envy is a misanthropic sadist, who uses his powers to torment his victims by taking on the forms of people's loved ones before killing them. He is responsible for murdering Maes Hughes, by impersonating his wife and rubbing it at his face before killing him. Envy is mostly seen manipulating Amestris's government behind the scenes with a string of mind games and murders. This all culminates in him killing Ed when he finds out that Envy is, in fact, the homunculus version of his half-sibling. Unlike other homunculi, who wanted to become humans, Envy was the sole exception, only working for Dante so he could kill as many people as possible, abusing both other homunculi and prisoners in the process simply for laughs. When captured by the Thule Society in his serpent form, Envy is kept docile by being allowed to painfully impale his father Hoenheim, with his fangs.
- King Bradley/Pride is the military dictator of Amestris and one of the aforementioned Dante's most trusted homunculi. He is the mastermind behind the events that caused the genocide in Ishbal, and worse yet, repeats the same actions in Reole in order to lead his own nation in destruction. At one point, he even releases the infamous Mad Bomber Solf J. Kimblee from prison and unleashes him upon Reole citizens in order to take care of the deed as fast as possible. While mainly assisting Dante in her plans to create the Philosopher's Stone all over again, it is made clear that Bradley enjoys committing these deeds for the sake of "purifying" the population and expanding the country's territory. After Martel finds out about Bradley's true identity, he proceeds to murder her cold-bloodedly in front of Al in order to keep her silent. In the final arc, Bradley plays a sadistic cat-and-mouse game with Roy Mustang, torturing him both physically and emotionally, even bringing up the tragic fact that he couldn't save his best friend from a certain death. When his own son steps in the hopes of helping his father, Bradley strangles him to death while ranting about being an agent of God.
- The aforementioned Solf J. Kimblee stands out as even more insane and psychotic than his manga counterpart. A state alchemist with the ability to turn objects—and people—into explosives, Kimblee Loves the Sound of Screaming and earned a reputation during the Ishbal genocide for his ruthlessness. As seen in early flashbacks, Kimblee was responsible for creating mass destruction in his district, all while laughing like a maniac. He also tortured Scar by sadistically blasting him apart one piece at a time, giving him the distinctive mark in his forehead. Later, Kimblee escapes the prison by using a fellow inmate as a bomb and starts working for Greed before betraying him to Frank Archer and being indirectly responsible for the Devil's Nest massacre. After his reinstatement, Kimblee reenacts the Ishbal genocide in Reole and tries to murder Al by transforming him into a walking time bomb.
- The anime incarnation of Barry the Chopper is far more vicious and horrifying than his original. He was once a simple butcher living in Central City, but when he grew bored of chopping up animals, decided to butcher his wife and found he loved the sensation and followed by gruesomely murdering many young women. Barry's killing spree came to a temporary halt when he was arrested after trying to kill the Elrics' childhood friend, Winry. Rather than be executed, Barry was experimented on, had his soul bound to a suit of armor, and was used as a guardian for the Fifth Laboratory. After it was destroyed, Barry slaked his bloodlust by joining a group of mercenaries to slaughter a camp of harmless Ishvalans.
- The Conqueror of Shamballa: Thule Society Chairman Dietlinde Eckhart is the Big Bad and an occult supporter of the Nazi party trying to reach the titular Shamballa to gain the power to conquer the world. Capturing Envy to open the gate to the other world, Eckhart keeps the homunculus docile by allowing him to bite into Hoenheim, leaving the man in agony. When Hoenheim sacrifices himself to open the gate, Eckhart, no longer needing Ed's alchemy, shoots him and leads an assault into his world. Enthralled with her newfound ability to use alchemy but fearing others with the same power, Eckhart tries to destroy the very world she once sought to conquer, a xenophobic hypocrite who would not tolerate anyone but herself having authority.
- Sho(u) Tucker, the Sewing-Life Alchemist, is revealed to have fused his own wife with a dog to turn her into a chimera, a twisted parody of life that suffers in perpetual pain. Later performing the same treatment with his own daughter, Tucker defends his actions by claiming it is completely natural to perform unethical experiments solely on the basis of being able to. Being beaten and imprisoned by Edward Elric, Tucker later joins a military coup where he helps to create countless Mannequin Soldiers to unleash upon the civilian populace solely to spite Ed, without a single care for the lives that will be lost.
- General Hakuro is a ruthless military officer seeking a military coup. Manipulating conflict, death and murder across Amestris, Hakuro recruits Tucker and reveals the truth of the Philosophers Stones as the amalgam of fused human souls and lives, flashbacks showing that Hakuro had thousands of prisoners and innocents painfully melted down to create thousands and thousands of stones. Upon confronting Edward, Hakuro plans to unleash the cannibalistic Mannequin Soldiers on Amestris to kill until Hakuro can seize control of the country, driven by nothing but a hunger for power.