Complete Monster/Buffyverse

Amongst the numerous vampires, demons, and other creatures inhabiting the Buffy Verse are some loathsome villains. Some are actual monsters, while others are just monstrous.

The Entire Buffyverse

 * Angelus is one of these, particularly so when contrasted with every other vampire in both series. He's explicitly referenced numerous times as THE worst vampire ever. By way of examples, Spike and Drusilla had a genuinely loving relationship, Spike looked up to Angel as a friend and mentor, Darla was devoted to the Master and loved Angel (even though it's implied she knew he was incapable of loving her back), Wishverse Willow and Xander seemed to truly care for one another (notice how overjoyed evil Willow is when she finds Xander alive after seeing evil Xander killed), and the Master was rather fond of Darla (and, in the Wishverse, Xander and Willow) and mourned her death. In contrast, Angelus was utterly devoid of all human feeling and considered Mind Rape to be an art form. One can also see a strongly abusive streak to his relationships with Darla and Drusilla, who in turn practically worship him for such cruelties inflicted on them as much as anyone else. Besides countless tortures, rapes, and murders for his own amusement and attempting to send the entire world to Hell, two of Angelus' crimes truly stick out: posing as a priest, he made an innocent, chaste girl his 'project,' where he slowly tempted her to evil, then brutally murdered her family. He hunted her down to a convent and slaughtered everyone in the day she was to take her vows before turning the now insane girl into a vampire to preserve his masterpiece. Second incident...Jenny Calendar. After brutally murdering her, he put her corpse in her love interest's bed...before sending him love notes, champagne, leaving flower petals strewn along to make it look like it'd be a romantic encounter...right until he found the body. In his spinoff, he is also shown mercilessly manipulating Spike in a flashback. It puts things into perspective when the Master (an ancient and demonic vampire head of an order which worships Eldritch Abominations and seeks to bring about the end of the world) refers to Angelus as "the most vicious animal I have ever known".
 * The Judge was a demon who sought to kill anyone with a shred of humanity. Spike and Drusilla were nearly killed because of their love for one another and a side character was killed because he had a love for knowledge. Angelus, on the other hand, was deemed "clean of humanity". He had no redeeming values whatsoever.
 * Perhaps more than physical torture, though, Angelus enjoys psychologically tormenting people. In season 2 of Buffy the Vampire Slayer, he stalks Buffy, never hurting her physically, but making her terrified for her own life and that of her mother and family. He turned Buffy's classmates and friends just so they could deliver a message when she came to stake them, so she would be absolutely sure that he was the one who killed them. He would also draw pictures of Buffy, and also Willow and her mom, while they were sleeping, and leaving them there to be found when the person woke up. The fact that he was a really good artist just made it a thousand times worse. Angelus also constantly taunted her about their former relationship and exactly what his emergence had entailed. And most of all, Angelus mocked her when she couldn't kill him, because he had Angel's face.
 * "The Watcher's Guide", a book on the series written after the second season was over, even states word-for-word that "Angelus is a complete monster."

Buffy the Vampire Slayer

 * Lothos, the first enemy Buffy ever faced as the Slayer, is a vampire king who has killed numerous Slayers over the centuries. Arriving in Buffy's hometown, Lothos starts a new killing spree to track down Buffy and take over the city, having his follower Amilyn track down and turn numerous people into his vampiric army for him and bring Lothos new victims to feed on, even turning one of Buffy's friends to find her and kills another. During his first confrontation with Buffy, Lothos kills her watcher Merrick by turning his stake onto him, letting Buffy go at the time as he was expecting more of a challenge. Later, Lothos leads his minions on an attack at the school, killing several students. Lothos is completely indifferent towards his followers and their deaths, as seen when he refuses to save Amylin when Buffy stakes him, giving him an unsympathetic smile as he mockingly plays a fiddle. After Lothos fails to hypnotize and/or seduce Buffy, Lothos stops his flirtatious advancements in favour of going in for the kill, putting his sadistic personality on full display as he notes to the rest of the students that he will kill them all himself once he's done with Buffy.
 * Considering he only appeared in a single episode, the vampire Zachary Kralik from Season 3's "Helpless" did a remarkably good job in appearing as one of these. At this point in the show, vampires in general were seen as being a fairly low-level threat, but Kralik managed, partially through a quasi-Diabolus Ex Machina and partially through his method of murders, predatory behavior, and own utter hideousness, to be thoroughly terrifying and completely monstrous by regular vampire standards. It's impressive that even when given a Start of Darkness story involving the abuse he suffered from his mother, the viewer still cannot feel for him in the slightest.
 * Season 7's Caleb is a defrocked priest turned Serial Killer of young women, who uses the trust that people have in him to get closer to his victims, before torturing and killing them. In his first appearance, he guts one of the Potential Slayers and leaves her at the side of the road, as a message for Buffy. He then kills another one of the girls during a battle, mangles the arm of another, and puts out Xander's eye, cracking bad jokes the entire time. He also coordinates the actions of the Bringers, organizing the bombing of the Watcher Council's headquarters (resulting in most of their deaths), arranging the assaults on numerous Potentials, and trying to have Faith killed while she was in prison. A misogynistic sadist, who believes that all women are whores and deserve what he does to them, Caleb is The First Evil's right-hand man, and lives for the oncoming apocalypse, seeing the end of the world as a way to dispose of all those who do not share his mad religious convictions. He also gets a real kick out reenacting his murders with the shape shifting First. Perhaps the most frightening thing about Caleb, however, is that he is regular human, and there was never any Freudian Excuse in sight.
 * Simone Doffler, the Big Bad of the season 9 comic, initially started out as a rebellious Slayer who didn't see the value of the lives of others and believes that Slayers are superior to normal people, and therefore should rule over them. In an attempt to soften her she was put under the watch of Andrew Wells, hoping to soften her; instead she goes rogue and steals a demon to use as a weapon and asks Buffy to turn over Andrew, who she wants to kill since he annoyed her. She also led a small but growing army of rogue slayers who set up base on a small island, where Simone beat up an old woman who gave them food and shelter. Simone's gang would later commit acts of terrorism, including raiding a military base and killing their general, relishing in the fearsome reputation it gave the slayers. Later Simone learned of the zompires, and plotted to find a way to become one and keep her mind intact, for the sole sake of killing Buffy, with which she has become obsessed. To experiment, she feeds her own followers to them. When she learns Buffy's sister Dawn is dying, she manipulates their friend Xander with a chance to save her by finding the deeper well. Her true intention was to awaken the Old One, Maloker, so that he would sire her into a vampire.

Angel

 * Apart from Angelus, Angel also features the episode "I've Got You Under My Skin", in which Angel and his gang tries to exorcise a demon from a young boy named Ryan Anderson that had been causing the child to start fires and attempt to murder his own sister. The twist comes when
 * Marcus from Season 1's In the Dark is hired by Spike to extract information from Angel on the whereabouts of the Gem of Amarra, a magical ring that gives Vampires complete invulnerability from harm and their usual weaknesses, such as sunlight. A man obsessed with the "art" of torture, Marcus is rumored to have inspired some of the more favored and gruesome techniques used through history. Serenely, playing Mozart in the background, Marcus falls into a rhythm of torturing Angel, impaling him with hot pokers then asking Angel what he truly wants. When Angel refuses to answer, the cycle begins again, each time with Marcus hoping to truly break Angel and lay his soul bare. He also burns Angel with sunlight and forces him to suspend himself in the air with his chains in order to avoid being incinerated. Marcus is also a pedophile who specializes in feeding on and molesting children, and, after Marcus betrays Spike and takes the ring for himself, the first thing he does with his newfound invulnerability is attempt to murder a group of boy scouts, only being stopped due to the timely arrival of Angel.
 * Darin MacNamara from "The Ring" is a greedy ringmaster and, despite being only human, is one of the most monstrous villains that Angel has ever faced. Running an arena where he kidnaps other demons and forces them to fight to the death, Darin refuses to let any of them go until they've had their 21st kill. Anyone who tries to escape gets incinerated by an electric bracelet they are forced to wear, and anyone who refuses to fight gets tortured. After kidnapping Angel, he holds Darin's brother and partner-in-crime hostage as a way of forcing him to let them go, stating "he's your brother". Darin, without any hesitation or look of remorse, shoots his brother to death, simply explaining, "Now he's my dead brother", and has Angel tortured afterwards. After Angel refuses Darin's offer to be let free for his own financial gain, Darin, believing Angel had outlived his usefulness, puts him in a fight against the ruling "champ", who's at his 21st fight, in hopes of him getting killed. Greedy, ruthless, and even seeing his own brother as a mere tool, Darin proved to be more monstrous than any of his demonic contenders.
 * Among Angels villains of the week, it's hard to top Billy Blim for clearly falling into this category. While appearing to be a normal young man, he was actually a demon filled with an extreme power of misogyny and had the power to turn any man he touched or who came in contact with his bodily fluids into someone extremely savage and brutal toward anyone female. And he had no real reason to be doing this; rather, he appeared to do it only for his own sheer amusement. The fact that it was actually the normally very cold and amoral Lilah who took him out says volumes as to how horrible he was.
 * It gets worse than that. According to Word of God, they personally believe that Billy was conceived when a demon woman - a good demon woman - was raped by an evil human man. This is just as screwed up as it sounds - Billy was doomed to be a fucked-up man since he came into existence. This only justifies his power, however, and not why he uses it, which definitely makes him fulfill the role of a Complete Monster.
 * Matthias Pavayne, also known as "The Reaper," from season 5's "Hell Bound," is a malevolent ghost haunting the L.A. office of Wolfram &amp; Hart. A Mad Doctor and Serial Killer in life, Pavayne performed fatal surgeries on his victims before moving on to dismembering them in ritualistic killings for over twenty years. Sacrificed by Wolfram &amp; Hart to deconsecrate the holy ground on which they were to build their Los Angeles office (a task which required a particularly evil soul), Pavayne's spirit endured as a ghost. To avoid his fate of being sent to hell, Pavayne tortures the souls of other people who died in the building, condemning them to hell in his place. Exploiting the High Turnover Rate at Wolfram & Hart, Pavayne spends over two hundred years cheating damnation and reveling in his power over others, with Wolfram & Hart being completely devoid of other ghosts by the time Pavayne's presence is uncovered. When Spike becomes a ghost bound to Wolfram & Hart, Pavayne targets him as his latest victim, tormenting Spike with visions of Pavayne's past victims. When Angel and his team bring in a psychic to help Spike, Pavayne gruesomely murders her to keep from being detected. After revealing himself to Spike, Pavayne physically and psychologically tortures him before trying to throw him into hell. When Fred tries to make Spike corporeal again to save him, Pavayne starts strangling her, intending to force Spike to choose between saving himself and letting her die, or saving Fred and allowing Pavayne to send him to hell. A terrifying and sadistic psychopath, Pavayne condemns countless souls to hell in order to save himself, and takes a deep pleasure in doing so.