->''"A 60-year-old woman. She did things she never expected to do...Do you wanna hear how, in the evening, she said she would do anything as she begged for her life? Or how, in the morning, she begged me to take her out of her misery? Which do you think I enjoyed more?"''
-->--'''William Lewis''', ''Series/LawAndOrderSpecialVictimsUnit'', "Her Negotiation"; after telling Detctives Benson and Amaro in graphic detail what he did to one of his victims (including putting out cigarettes on her)

Although ''Franchise/LawAndOrder'' features countless killers (and non-killers) who [[MoralEventHorizon committed heinous crimes]] without remorse, many of them have a typical motive such as {{Greed}} and {{Envy}}, or sometimes even a good FreudianExcuse or [[SympatheticMurderer even sympathize with]]. Some however, have the (dis)honor to be called a [[CompleteMonster monster.]]


* Constantin Volsky, the [[TheMafiya Russian mob boss]] from season 9's [[Recap/LawAndOrderS9E23RefugePartOne two]]-[[Recap/LawAndOrderS9E24RefugePartTwo part]] finale "Refuge," ordered an innocent man murdered and dismembered because he had a relative who wouldn't go along with a money-laundering scheme. When he finds out that the key eyewitness for the prosecution is a 6-year-old boy, [[WouldHurtAChild he sends assassins to kill him]]. They kill his mother and an A.D.A. The boy lives, but only because they didn't cut deep enough into his throat. In the second part, he orders the bombing of the precinct where the police protagonists work, [[ForTheEvulz just for giggles]].
* Mark Bruner from the season 14 premier "[[Recap/LawAndOrderS14E1Bodies Bodies]]" [[SerialRapist raped]] and [[SerialKiller murdered]] no less than 17 teenage girls and kept most of their bodies rotting in an undisclosed location so he could go and admire them as they decayed. He terrified his original defense attorney so much that [=McCoy=] helped to get her reassigned, terrified Serena, visibly unnerved Briscoe, Green, and [=McCoy=]. What made him truly monstrous was his refusal to reveal the location of his dumping ground so that his victims might be identified, specifically to torture the parents so that they couldn't find closure, and to torture Jack with the knowledge that he couldn't give them that closure.
* Leon Vorgitch from season 17's "[[Recap/LawAndOrderS17E9Deadlock Deadlock]]" was in prison for killing five people. He then kills two guards and escape from prison. When the detectives come for him it results in even more deaths, including a [[WouldHurtAChild classroom of children]] he had taken hostage (he mistook a truck backfiring for police shooting at him). When Detective Green asks Vorgitch why he killed the kids, he laughs and says "Why not?" In the end, he brags to Jack and Connie that he will escape again and kill both of them.


* Darryl Kern from season 2ís "Manhunt" is a {{serial rapist}} and {{serial killer}} who made a habit out of abducting, raping, torturing and killing women. He was a [[SociopathicSoldier former soldier who was discharged because he believed soldiers liked killing]]. His journal states that he is planning to survive an upcoming radical war, and create a new generation from sex slaves, but later admits during questioning that he's simply [[ForTheEvulz having fun at the expense of the police]]. When his hideout is found, at least fifteen bodies are found buried in his yard alone. He also has his assistant, a mentally fragile man named Posey, help him kidnap a woman and her young daughter. Kern then [[YouHaveOutlivedYourUsefulness kills Posey]] , and plans to kill his hostages but is arrested by Canadian police.
* [[DepravedBisexual Charlie Baker]] from season 4's "Dominance" has murdered eleven people in about a week, after forcing them to have sex with each other first or raping the victims himself. Then he kidnapped two women, killed their boyfriends, and kept them captive on a roof. He's also been raping his little brother and beating his alcoholic father all along.
* Eugene Hoff, alias Abraham Ophion, from season 6ís "Charisma," is the [[WouldHurtAChild pedophilic]] leader of a CorruptChurch of his [[{{Cult}} 100 followers]], which included his pre-teen victims and their families. Hoff separates the married couples, because he said that they couldn't be soldiers of God if they were slaves to the flesh, and uses all the women and girls of his cult for sexual favors, fathering 1 living and 6 dead children with them. His earliest victim was a 4-year-old Jamie Buchman, who her father caught in the same room with a near-naked Hoff, causing his family to leave the church. Growing paranoid, Hoff began to prepare his followers for war, filling their heads with the idea of the U.S. Government coming to kill them. He was also a {{greed}}y man, killing John Cramer and lying to his wife for John's million-dollar bank account and only keeping his latest victim Melanie alive so he can claim her two-million-dollar trust fund after their baby is born. Hoff is ultimately a depraved individual who [[AGodIAm believes himself to be greater than God]].
* [[GunmanWithThreeNames Victor Paul Gitano]] from season 7's "Fault" was a {{sadist}}ic [[WouldHurtAChild pedophile]] that lures kids in, then [[SerialRapist rapes]], [[ColdBloodedTorture tortures]], and [[SerialKiller kills]] them. He doesn't discriminate by gender either. On top of that, when trying to hunt Gitano down, things don't quite go as planned. Not only does he kill one of the two kids he had with him in a subway station full of people by slashing his throat, he almost killed Benson the same way. Then, when they corner Gitano in a warehouse, he manages to get behind Stabler and hold him at gunpoint with a shotgun. Gitano, despite knowing he'd get caught or killed at this point, outright boasts that he killed the other child he had (who was a girl) and bragged that she was a "slut" and a "real little whore" before killing her, even though he never got the chance to molest her.
* [[SerialRapist Bill Harris]] from season 12's "Behave" is responsible for nearly a dozen rapes. He developed a special interest in one of his victims, Vicki Sayers, and repeatedly tracked her down whenever she was on the verge of putting her life together.
* [[SoftSpokenSadist William]] [[FauxAffablyEvil Lewis]] from the season 14 finale and season 15 is a {{serial rapist}} and {{sadist}}ic [[ColdBloodedTorture torturer]]. His MO is going from state to state, kidnapping, raping and torturing women for hours and even days on end under different aliases, regardless of age. When he was young he watched his babysitter get raped and killed in front of him; he describes it as the best day of his life. Eventually he kidnaps Detective Olivia Benson, forces her to watch as he kills the father and rapes the mother of his defense attorney. After [[CopKiller killing a cop]] and taking Benson to a house to rape her, he takes a maid and young girl hostage. When Benson turns the tables on him, he deliberately tries to provoke her to kill him. During his trial, he makes Olivia relive the experience. After his escape, he kills another cop, rapes a nurse and kidnaps a young girl. When Benson confronts him, he takes her hostage again, but becomes turned off by his initial molestations, so he decides to force her into a game of RussianRoulette.