- Sourcery: Ipslore the Red, having been thrown out of Unseen University for taking a wife and having children, vowed revenge, his obsession causing him to discard his previous love. Siring his eighth son Coin, a sourcerer—a wizard cable of creating magic granting them near unlimited power—merely as a tool for revenge, Ipslore cheated Death by binding his spirit to Coin's staff, threatening to kill the boy should Death remove him. Over ten years Ipslore molded Coin into an utterly dependent killing servant, punishing even the slightest defiance with Electric Torture. Using Coin to murder several wizards to gain him control of the university, as well as killing one for being kind to his young child, Ipslore sets the university loose against the city, turning Lord Vetinari into a lizard and letting the wizards terrorize the helpless population of Ankh-Morpork. Under Ipslore's rule, anyone who attempts to interfere is killed regardless of their inability to stop Coin. Letting his hubris overtake him and still hungry for more power, Ipslore has Coin freeze the Discworld pantheon, now desiring to rule the entire disc, completely uncaring his actions could bring about the collapse of reality itself from the Ice Giants arising or the excess magic attracting the Things from the Dungeon Dimensions.
- Wyrd Sisters: Lady Felmet is a vicious Lancre aristocrat, who persuades her husband Leonal to murder King Verence I and take the throne, solely for her own benefit and power. Disposing of anyone who dares disputes their claims that Verence's death was accidental, upon ascending Lady Felmet encourages a brutal suppression of peasants, including cutting down the forests and burning down people's homes, sometimes whilst they're still inside; while using the Fool to spread a propaganda campaign turning the people against the witches. An utter sadist, Lady Felmet personally enjoys inflicting inventive tortures upon each and every one of her captives. Even when forced to face her own evil by Granny Weatherwax magic, Lady Felmet reveals herself to not only be fully aware but proud of her cruelty, happily boasting that she would do it all again if she could.
- Hogfather: Jonathan Teatime is a sadistic assassin feared even amongst hardened criminals. Implied to have killed his own parents, Teatime has a penchant for excessive slaughter. In one instance, Teatime nailed his target's pet dog to the ceiling for barking too much and killed his servants because he didn't want them to barge in on him. After the Auditors hire Teatime to kill the Hogfather, Teatime abducts a tooth fairy to use her magic to make all the children in Discworld stop believing in the Hogfather in order to kill him, causing a void in Ankh-Morpork's magic that wreaks havoc in the process. Teatime, unlike other members of the Assassins' Guild, shows no regard for the lives of civilians or his own men, in one instance killing a stagecoach driver out of boredom while chatting with him and in another instance having a locksmith working for him dropped down a long spiral staircase to a painful death when he's no longer useful. When Death and Susan foil his assassination attempt, Teatime tails them to the nursery Susan works at in an attempt to kill Death.
- The Fifth Elephant: Wolfgang von Uberwald is a sadistic werewolf who is obsessed with the purity of bimorphic werewolves, even murdering his own sister for failing this test. A Serial Killer who savors hunting helpless human prey, Wolf allows them glimpses of hope by fleeing him, only to set upon them and rip them to shreds. Wolfgang does not bother to play by the rules, relishing in the sadistic slaughter of those he hunts. Leading a werewolf conspiracy to plunge Uberwald into war, Wolfgang intends on creating a widespread slaughter more for the fun of it than any true advantage or power.
- Night Watch:
- Carcer Dun is a sociopathic Cop Killer initially wanted for murdering three of the Ankh-Morpork City Watch, who is sent back in time along with Sam Vimes after feigning surrender and temporarily blinding him. Murdering John Keel, forcing Vimes to take his identity, Carcer enlists with the Unmentionables and teaches them a new torture trick, later threatening to kill "Young Sam" to destabilize time further. Escaping from an assault, he threatens to torture a child and uses the information obtained to force two unwilling commanders of the army into a full-frontal assault on the Treacle Mine Road barricade, in a deliberate attempt to maximize casualties and spite Vimes's attempts at damage control, which escalates into dozens of deaths and injuries. Once promoted to Captain by Lord Snapcase and ordered to lead a death-squad on "Keel", Carcer defies orders and orders he and Young!Vimes be taken alive while instructing his men to kill anyone else, including Reg Shoe who posed no threat. Upon returning to the present, Carcer vandalizes the tribute to Keel just to spite his rival and makes a final attempt on Vimes's life for no reason but his own amusement.
- Captain Findthee Swing, the leader of the Cable Street Particulars, is the reason his time period is so corrupt and oppressive. Swing is a Tautological Templar obsessed with craniometrics, using people's head measurements arbitrarily to decide whether someone is good or bad in his eye, even taking on Carcer Dun as his sergeant. Responsible for ensuring Homicidal Lord Winder's dominion, Swing has any suspected dissidents disappeared to his cells and sent his men out to incite violence against the city's watch and militia's on and around the Glorious 25th May, sparking several riots. Upon entering the Particular's headquarters, Vimes discovers a dungeon full of people who Swing had physically and mentally tortured into confessing to his accusations; one person so broken that he does not resist when Vimes kills him without hesitation. Murdering his own torturer to destroy the evidence of his crimes, Swing attempts to kill Vimes even as his headquarters burns.
Tiffany Aching (young adult series)
- I Shall Wear Midnight: The Cunning Man was a witch-finder in life, but persisted as a spirit of pure hatred after his original body disappeared, and resurfaces every few decades to target new witches after each defeat, killing them if they lose. Cunning Man targets the Chalk with his Hate Plague, turning them against Tiffany Aching and framing her for the death of the previous Baron, while also making the Baron's son, Roland, turn against her and engineering a situation so a drunken cook falls to her death and Tiffany is blamed. Upon discovering Roland's fiancée Letitia is also a witch, Cunning Man attempts to murder them both multiple times, then possesses a criminal and has it kill its canary for no reason, before making a final attempt on Tiffany, Letitia, Roland and Preston's lives. Seeking to end witchcraft once and for all and uncaring of whose lives he ruins in the process, the Cunning Man is fueled by sheer malice unmatched by any other foe Tiffany faces.
- Going Postal (2010 Sky adaptation): Both the Big Bad and one of his chief lieutenants are much worse in this adaptation than in the source material:
- Reacher Gilt is the corrupt head of the Grand Trunk after the Dearhearts are bankrupted, running it into the ground to line his own pockets. Having multiple Postmasters and the uncovered spy John Dearheart assassinated by Mr Gryle, Gilt half-heartedly attempts to dissuade Moist von Lipwig from restoring the defunct Ankh-Morpork Post Office and then orders Gryle to burn the office down and kill Moist and his staff when this fails. As the rivalry between Trunk and Post Office heats up, Gilt slowly loses his grip on sanity, beating his chief accountant Horsefry to death for keeping records too meticulously and threatening to drop employees to their deaths when wrongly suspecting them of sabotage, not caring when his chief engineer Mr Pony protests that the employee is his niece and later threatening her if the Clacks loses its race with the Post Office. When seeming to have won, Gilt tries to speed up Moist's scheduled demise, and when finally exposed as a criminal, spitefully smashes an omniscope, uncaring of the potential harm to everyone and almost causing Moist to be hanged.
- Mr Gryle is a Banshee and sadistic assassin working for Gilt, proudly describing himself as "the Post Office curse". Having killed the four Postmasters before Moist von Lipwig in ways mistaken for gruesome accidents, Gryle also murders John Dearheart, Adora Bella's brother, just after sarcastically announcing his presence, and mocking him before detaching his safety harness and letting him fall to his death. Later told by Gilt that Moist is a "nuisance", Gryle burns down the Post Office—nearly suffocating Tolliver Groat—and attempts to savagely kill Stanley while bragging about eating his own grandmother. Finally confronting Moist when he attempts to rescue Stanley from the blaze, Gryle gleefully confesses to his previous murders—uncaring that this gives Gilt away—and brags that John "squealed like a pig" as he tries to complete his "collection" of Postmasters by ending Moist's life.