"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
- Father is a being from beyond the Gate given form as the "Dwarf in the 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 to absorb its power, Father demonstrates cold sadism when he faces Hohenheim and the latter's children Edward and Alphonse Elric, 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 Doctor with the Gold Tooth was commissioned by Father to create the Homunculus Wrath, which he did by indoctrinating dozens of children as potential candidates. Inserting Philosopher's Stones into the subjects' bodies, the Doctor killed all except one in his diabolical experiments, leaving the failures mindlessly only able to follow his orders. When confronted by Roy Mustang and his group, the Doctor tries to force Mustang into opening the Gate of Truth for Father's plan by slitting the throat of his Love Interest and shows only apathy to the notion his helping Father will lead to the deaths of everyone in Amestris.
- "An Alchemist's Anguish": 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.
- The Sacred Star of Milos: Atlas is a power-hungry Lieutenant in the Cretan military assigned to guarding the Crichton alchemist family. Murdering the parents for their research on the Sanguine Star, Atlas also skins the face of their older son Ashleigh to take on his identity. Years later, as "Melvin Voyager", Atlas breaks out of prison using an explosion to find Ashleigh's sister Julia, posing as her brother to manipulate her and her group, the Black Bats, into helping him create the Star. Using the transmutation circle around Table City, Atlas tricks the Bats into committing terrorist attacks, thinking they are fighting for their country Milos, before betraying them, killing their leader—his own co-conspirator—and countless Amestrian soldiers to create the Star with their deaths.
- Dante is a vain 400-year-old alchemist who keeps herself alive by sacrificing lives to allow the creation of a Philosopher's Stone to transfer her essence into younger bodies, sacrificing thousands and killing the previous inhabitants of her new body. In the nation of Amestris, Dante installs one of her Homunculi servants, Pride, as Führer of the country and has him enact numerous bloody conflicts, in the hopes that doing so will push a talented alchemist to create a stone for her to use to retain her youth. Keeping the Homunculi in order with the false promise of restoring their humanity with the Stone, Dante even uses Sloth's likeness of her previous lover's wife torment him and his sons. Selecting the teenage hero Ed's Love Interest as her next body, Dante states her intent to have sex with him and hypocritically rants that her oppression of humanity proves her to be their immortal protector.
- This version of Führer King Bradley is the Homunculus Pride and Dante's right-hand alongside Envy. Masterminding the genocide in Ishbal and repeating the atrocity in Reole, Bradley even unleashing a psychopath to hasten the second blood conflict. Using his position as Führer to help Dante create conflict in the hopes of a desperate alchemist creating another Philosopher's Stone, Bradley also enjoys the power of taking territory and murders any who find out about his Homunculus origins. Tormenting Roy Mustang when the two face off in the final arc, Bradley even strangles his own son to death in anger when the boy accidentally reveals his weakness.
- Solf J. Kimblee, the Crimson (Lotus) Alchemist, 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 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. Kimblee is later assigned by Pride to reenact 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.
- Major 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.