{{Complete Monster}}s from the ''Franchise/HarryPotter'' franchise.

* [[BigBad Lord Voldemort's]] defining characteristic is [[TheSociopath being a sociopath]] [[EvilCanNotComprehendGood who cannot understand love]] and has no remorse for any of his actions. His EstablishingCharacterMoment is killing two young wizarding parents and [[MoralEventHorizon his attempted murder of their one-year-old]]. He started two genocidal wars against Muggle-born wizards, Muggles, and their supporters alike, out of a [[ANaziByAnyOtherName Nazi-esque]] desire to create the "perfect" wizarding world; [[BoomerangBigot this despite the fact that he himself is half-Muggle]]. Most heinously, he is well aware that using the spell to murder other humans will split his soul irrevocably, because of how evil the spell is - and uses this knowledge to create immortality for himself. He gets even worse in the later books, as his magical transformations and soul-mutilations have [[VillainousBreakdown taken a toll on his mind]], driving him pretty much completely AxCrazy. Throughout the books Voldemort tried to open the Chamber of Secrets as a teenager to wipe out all "mudbloods" (witches or wizards born of two non-magical individuals) in Hogwarts, killed his father and grandparents and framed his uncle for the crime, ordered Cedric Diggory's murder, murdered an entire family [[DisproportionateRetribution because the mother didn't know where someone Voldemort was looking for was]], [[ShootTheMessenger indiscriminately killed his own followers when given bad news]], and killed [[spoiler:the seemingly loyal Severus Snape]] because he believed his minion's death would grant him greater power. ''[[Literature/HarryPotterAndTheHalfBloodPrince Half-Blood Prince]]'' and ''[[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]]'' explain [[FreudianExcuse his transformation into a monster]], but serve more as a cautionary tale than a true FreudianExcuse: [[spoiler:his mother basically enchanted and raped his father, and when his father was freed of the enchantment, he bolted, and his mother died of despair. This led to him growing up without any idea of love or what it entailed.]]
* [[TyrantTakesTheHelm Dolores Umbridge]] is a domineering and abusive matron figure and a bureaucrat whose pettiness and personal failings cause catastrophic harm to those under her control, all while maintaining a [[StepfordSmiler kind]] [[BitchInSheepsClothing grandmotherly]] [[FauxAffablyEvil veneer]]. In ''[[Literature/HarryPotterAndTheOrderOfThePhoenix Order of the Phoenix]]'', she becomes a [[SadistTeacher teacher at Hogwarts]] and forces students who speak up against the Ministry of Magic ([[DisproportionateRetribution or just displease her]]) to use the Blood Quill, which [[ColdBloodedTorture basically uses the writer's blood as ink and can result in permanent scarring]]. At one point she threatens to use [[AgonyBeam the illegal Cruciatus curse]], which has been shown to cause unimaginable pain, and reveals that she sent the two Dementors after Harry and his cousin. In ''[[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]]'', she willingly supports the Death Eater-controlled Ministry, and holds [[KangarooCourt hastily rushed and sadistic trials against Muggle-borns]], where she accuses them of stealing magic and gleefully sentences them to the Potter-verse's FateWorseThanDeath, the [[YourSoulIsMine Dementor's Kiss]]. She is shown to greatly enjoy [[MindRape psychologically torturing]] her victims, and delights in her new post.
* [[TheSociopath Bellatrix Lestrange]] is a [[PsychopathicManChild psychopathic]] female Death Eater who seems to be motivated primarily by [[{{Sadist}} her desire to inflict as much pain on as many people as possible]] in the name of Voldemort's cause. Bellatrix's [[AxCrazy insanity]] makes her an [[TheUnfettered unfettered]] case of TheFundamentalist, and while Voldemort is a cold and unfeeling murderer, Bellatrix is gleeful cruelty incarnate. She has a special fondness for torturing people with the Cruciatus curse, and tortured Neville Longbottom's parents to the point where they exist in near-comas, and will never recognize their own son again. She is also an accomplished arsonist, burning down multiple residences basically just for the sake of it. She's the cause of death for half of her non-Death-Eater family members, including [[spoiler:Sirius Black and Nymphadora Tonks, as well as Dobby]], and delights in the torment these deaths cause; she also tried to kill Ginny Weasley during the assault on Hogwarts. Common readings of her also note that she is obsessed with Voldemort, and relishes his cause more than any other Death Eater in the series.
* [[PsychoForHire Fenrir Greyback]] is a [[OurWerewolvesAreDifferent werewolf]], but unlike werewolves who go helplessly violent in wolf form, he bites people in human form just for the [[CardCarryingVillain pleasure of ruining their lives]]. His actions are all-but-explicitly stated to be pedophilic in nature, based on what he did to Lupin. In addition, he is a [[ImAHumanitarian cannibal]], in both wolf and human form. He's shown trying to eat Harry at the Battle on the Astronomy Tower, wants to eat Hermione when Bellatrix is done torturing her, and attacks Lavender at the Battle of Hogwarts. He shows absolutely no remorse for doing any of these things, and [[SavageWolves takes a perverse delight in the damage he causes]]. The only reason he showed up at the Battle of Hogwarts was to engage in [[WouldHurtAChild raping and eating children, after all]].