Where the church, the Hunters' and the Rangers' guilds use rare gems for mana storage, the Catacomb Lords and affiliates use "gems of pain", created and charged with human sacrifices.
There is also a throwaway line about car gods becoming the receipents of human sacrifice on a scale unseen since the Aztecs.
Odin and Loki's plan is to start a war between the Old Gods and the New. Dedicating the divine blood spilled to Odin and the chaos to Loki.
Necromancy in An Army of the Dead involves human sacrifice. In the case where it was used in the story, an entire army is sacrificed. Strangely enough, by the good guys, and for good reason.
The Enemy's magic frequently makes use of human sacrifices. For instance, Thrembode the New kills a woman and mutilates her to disrupt a protective spell cast annually upon the city of Marneri.
It's a part of the Gingo-La cult's modus operandi. They kidnap innocent people and sacrifice them to appease their goddess.
Torak's Religion of Evil in The Belgariad collects its own followers' hearts at a prodigious rate: on one holy day, each major temple sacrifices 1110 people, the majority of the year's offerings. The culture of one Angarak nation revolves around avoiding being chosen: males spend their time saving to buy slaves to send in their place, while women stay perpetually pregnant to disqualify themselves. When Garion learns in The Malloreon that the sacrifices continued even after he killed Torak, he is appalled. Fortunately, he gets to nominate Torak's replacement.
"The Long Walk 2020": Women who no longer have anyone to support them — usually elderly widows, sometimes beggars — are sent into the titular long walk towards the mountains where the dragons live, to be devoured by the beasts in exchange for the dragons' protection against the demons. In the end, it's revealed that the women aren't actually devoured — most simply live the rest of their lives out in peaceful villages, while a few choose to transform into dragons themselves. The true nature of the deal, unbeknownst to humanity, is also to provide the dragons with a means to reproduce after the demons overran their old breeding grounds.
"The Nine Curves River": Played with. Nobody actually knows for sure what happens to the people who go into the grotto — speculation includes them being eaten by a dragon, becoming a dragon, or living forever in an Earthly paradise. It's not even completely certain if there is a dragon in there. All that's known for certain is that people who go in never come back out again, and if nobody's sent in once a year then the rain doesn't come.
The Burning Kingdoms: Emperor Chandra ordered his sister Malini and her maidservants to burn themselves alive as a sacrifice. When she refused, he exiled her.
"The Call of Cthulhu" features a police raid on a Cthulhu-worshipping voodoo cult that practices human sacrifice (they maintain that they can't be tried for murder because they have never killed anybody).
A Day of Fallen Night is prequel to The Priory of the Orange Tree, which is based strongly on the myth of Saint George. The old story of Lasia's king holding a lottery to sacrifice citizens to the Nameless One—a dragon of world-ending might—is repeated and retold. The River Lord of Seiiki eventually learns it from the lesser dragon Taugran and decides it's a great idea nominal safety and personal power. He makes his first sacrifice his own grandniece, Suzumai.]
Book VI of Caesar's Commentaries on the Gallic War claims that the Gauls frequently sacrifice humans, especially in the face of war or disease. More specifically, some of them place their human offerings inside huge statues made from wicker which are then set on fire, burning the victims alive. We thus have to thank Julius Caesar for The Wicker Man (1973).
In "Xuthal of the Dusk", Thalis dismisses how the god Thog claims victims as no worse than this; Conan disagrees because you don't need either.
When I was a child in Stygia the people lived under the shadow of the priests. None ever knew when he or she would be seized and dragged to the altar. What difference whether the priests give a victim to the gods, or the god comes for his own victim?
I shall take it with my bare hands, twisting it from your shoulders as the head of a fowl is twisted! Thus the sons of Kosala offer sacrifice to Yajur. Barbarian, you look upon a strangler of Yota-pong. I was chosen by the priests of Yajur in my infancy, and throughout childhood, boyhood, and youth I was trained in the art of slaying with the naked hands — for only thus are the sacrifices enacted. Yajur loves blood, and we waste not a drop from the victim's veins. When I was a child they gave me infants to throttle; when I was a boy I strangled young girls; as a youth, women, old men, and young boys. Not until I reached my full manhood was I given a strong man to slay on the altar of Yota-pong.
This is a common motif in the Mythopoeia of The Crocodile God, as it focuses on the precolonial Tagalog culture of the Philippines, and their shared cultural ties with ancient Polynesians. However, this does not make it a Religion of Evil; sacrifices were mainly practiced out of desperation, ironically to one of their NICEST gods—Haik, the Tagalog sea-god as well as the title's crocodile-god. In Mirasol's first lifetime, she was a chief's daughter who was (almost) ritually drowned as an offering to Haik because the village was suffering a drought, but he rescued her and gave them a dying whale for food. It's implied that this is why Haik began their Reincarnation Romance several lifetimes later, as he notes that she's been spiritually open to connecting with him ever since.
Daughter of the Sun: Followers of Iius, the God of Gluttony, lure people up to his lake for him to eat them.
The Devils of D-Day by Graham Masterton. George S. Patton had thirteen German prisoners of war, and a Frenchwoman accused of collaboration, sacrificed to get the assistance of the eponymous devils in winning World War 2. Turns out the Frenchwoman was innocent; she goes to Heaven, then gets resurrected as an angelic trap for the next time someone tries this stunt.
Deeplight: Before they tore each other apart in the Cataclysm, the gods were appeased by sacrificing randomly selected islanders. In truth, the sacrifices themselves meant nothing. It was the fear of the surviving people that fed them.
Diana Tregarde: In Burning Water, the "Texas Ripper" murders (thought to be the work of an ordinary serial killer by the cops) are actually a series of sacrifices to the Aztec gods.
In Pyramids, Pteppic is presented the case of a handmaiden who refused to be killed for the last king's funeral. When he asks if it was not voluntary, the priest agreed that yes, it was, and she didn't volunteer.
Bethan would have been one in The Light Fantastic, but she ended up being saved by Cohen, Rincewind, and Twoflower. Unusual in that she wanted to be sacrificed, because voluntary sacrifices get rewarded after they die (that, and it'd mean she spent her teenage years staying at home on weekends for nothing).
Guards! Guards!: When a dragon takes over the city, a suggestion is put forward to sacrifice a virgin to it to prevent any flame-related "incidents". It's noted that most of Ankh-Morpork's religions are very specific on the subject of sacrificing folk: Only criminals or volunteers. Of course, refusing to be sacrificed voluntarily is a criminal offense...
The Compleat Ankh-Morpork City Guide says that human sacrifice has largely ceased in the city, because there are very few people who volunteer, and of course they can only do it once. The Reformed Vampyre's Diary suggests that, if the temples are looking for women who look attractive in a nightdress and can be killed more than once, then this is a situation in which vampires and religion can possibly find some common ground.
Human sacrifice used to be a common practice in Divine Misfortune before it was made illegal. Doesn't stop cults and more unsavory Gods from partaking in it.
Doc Savage: The Shimba attempt to sacrifice Pat savage as part of a ritual to convince his followers of his magical powers in Land of Long Juju.
In general, there is the Death Curse a wizard can produce. This is a sacrifice of self wherein the wizard uses the last bits of life and magic they have inside to unleash a powerful, and usually fatal, attack on his or her enemies.
Summer Knight: It isn't that the person is special, but rather the Big Bad infused the would-be sacrifice with the mantle of the Summer Knight. If she kills the sacrifice on the Altar of the Stone Table on the Summer Solstice, the power will be given to Winter rather than returning to Summer as it should. The imbalance will give Winter an edge and decisive victory over Summer, resulting in the next ice age.
Death Masks: Nicodemus utilizes a human sacrifice as part of a plague's power source. He originally wants Harry, being a wizard, but when his nemesis Shiro, a modern-day paladin offers himself in Harry's place, Nicodemus makes the swap. It turns out Shiro was Secretly Dying of cancer anyway.
The evil coven sacrifices one of their own number of ex-wives to unleash a powerful bad luck curse on a woman who was suspected of going to marry their ex-husband and risk ruining their alimony. They chose her because she thought a girl named Inari was also a potential wife to their ex and tried killing Inari, not realizing Inari is the daughter of the coven's magical benefactor Lord Raith. Her father wasn't amused at all by that.
The coven's plan involves using Thomas Raith, a friendly vampire (and also son of the aforementioned Lord Raith), to empower the curse to kill Harry Dresden because Harry and Thomas are the last known bloodline of Thomas and Harry's mom, who cursed Lord Raith years ago with her Death Curse to not be able to feed on people, castrating him and his goals.
It's also referred to in the backstory of a character in Proven Guilty — Charity reveals that she was an attempted sacrifice to a dragon, until Michael showed up to save her. The result was a Rescue Romance.
Queen Mab requires Harry to kill the tortured, broken, and traitorous Winter Knight he seeks to replace in exchange for her power and help. The sacrifice had his tongue removed, eyes gone, body now tiny and frail from only getting enough nutrition to survive, and on his body were tattoos of the word "traitor" in many languages.
When Harry arrives at the home of the Red King, a priestess is offered to Harry as a would-be sacrifice. He refuses, to the irritation of his fairy godmother because she hasn't made a virgin sacrifice in ages.
The Red Court Vampires have built up a powerful magical curse to destroy Harry by sacrificing hundreds of people to prepare the curse, and at the right moment, the key sacrifice would unleash it. They plan to sacrifice Harry's daughter, who he didn't even know existed 96 hours before hand. Harry is able to turn this against them by sacrificing Susan, mother of Harry's child, and just-turned full vampire. She resists her inner demon and lets Harry kill her on the alter, so she, now the youngest of the Red Court, will spread the curse to every single elder member of the court.
Skin Game: The Gate of Blood, the final gate into one of Hades' personal vaults requires not just a human sacrifice, but one who will die willingly so their ghost may pull the lever to open the gate. Nicodemus sacrifices his own daughter because she is the only one he is certain will actually help him.
Ursula K. Le Guin's Earthsea: In The Tombs of Atuan, the God-King sends prisoners to the tombs as a sacrifice to the Nameless Ones. Arha must decree how they are to be sacrificed. (She has Guilt Induced Nightmares after.) Her own dedication was set up as a feigned this — a man wielded an sword as if to cut her head off, and was stopped.
Eddie LaCrosse: In The Sword-Edged Blonde, Queen Rhiannon was found with what appeared to be the remnants of a baby in a pot surrounded by occult runes, so the obvious conclusion is that she killed her son as part of a magical/religious ritual. She didn't — the baby was kidnapped and the Queen was framed.
Obviously, in the Aztec Empire depicted in El Conquistador there are plenty of this. But also in the Europes, as they sacrifice heretics, witches and stuff to the almighty man in the sky.
Evolution: This is portrayed as invention of an ancient human to remove her political opponents, under the guise of bringing rain — although, from her not entirely stable point of view, she very much believes that the sacrifices actually work. Fortunately, only two sacrificial victims are required before the rains come; she was quite prepared to work her way through the entire tribe.
The Faerie Queene: What would a tribe of savage cannibals without a pagan priest practicing human sacrifices? Ironically, this savage custom is what saves Serena's life, since the preparation for her ritual murder takes long enough for a knight to come rescue her.
In The Fall of Tartarus, by Eric Brown, a colony planet has its sun start to go nova. In the years before the planet is incinerated, a cult forms whose members believe that the nova is caused by a god, and that if enough pain is felt by its members, the phenomenon will stop and the planet will be spared. So they willingly undergo "penance", a process that begins with flogging and cutting, continues with progressively more radical mutilation (implied to be executed in medically sound conditions but with no anesthetic whatsoever), and ends with the members, now reduced to little more than eyeless heads on limbless torsos, being roped to a cross and exposed to the scorching heat of the oversized sun. For hours. The sun blows up anyway.
The Cult of Drumer in House of Hell would lure innocent passer-bys into their mansion headquarters, where they'll be drugged and sacrificed for their Satanic rituals. It helps that "Drumer" is an anagram for "murder"... you play as an unfortunate salesman whose car broke down in a storm late one night en route to a meeting, and your attempts to take shelter in the Drumer mansion have you getting abducted leading to the main plotline.
Spellbreaker have you dealing with druids as the main villains, who practices sacrificial rituals for opening portals allowing demons to enter our world.
In Night of the Necromancer you're the Lord of Valsinore Castle, who's unjustly killed during a quest. You return as a revenant and finds out the villains who arranged your assassination is now after your sister, intending to sacrifice her and it's up to you to prevent her from being killed at all costs.
Fire and Hemlock: Polly's hobbies include making up stories, a pastime in which she is joined by an adult by the name of Tom Lynn. Much like Tam Lin, he is the destined human sacrifice, paid to hell or something similar, for the immortality of someone else. It is implied that he can be saved if he can keep Polly as his friend for a defined period of time, but of course, it doesn't go so smoothly.
In The Folk Keeper, when the Folk become unruly, one of the ways they can be calmed is through a human sacrifice. However, this is generally not considered to be a morally acceptable method, and Folk Keepers are employed to placate the Folk through other means. Sir Edward, however, has been making human sacrifices to the Folk in secret.
In Andre Norton's Forerunner Foray, when Ziantha goes back in time, she finds herself in the body of a war captive, buried alive in a tomb as a sacrifice.
The Ghosts of Sleath To the titular village, Crusades veteran Sir Gareth Lockwood, in pursuit of immortality, sowed, in the village of Sleath, a tradition of occult rite — which saw many ritual murders.
In The Girl from the Well, the villagers of Aitou ritually sacrificed young girls. Their high priest made them think it was necessary in order to hold shut a Hellgate, when in fact the sacrifices were intended to give him the power to control the hellgate.
During the magical drought, the oldest dragons couldn't survive without the ambient magic. While many went to sleep, some, including Julius's grandfather the Quetzalcoatl, turned to human sacrifice to limp along. It wasn't enough to save him when his daughter Bethesda decided to kill him.
It's mentioned, however, that humans are by far the least magical species. Even during the drought, when they were the only ones besides dragons who had any magic whatsoever, it was such an incredibly small amount as to be not even worth mentioning. Therefore, what little human sacrifice dragons were doing during the drought disappeared entirely afterwards.
Amelia: So long as the teleporting gets done, I don't care if you make the circle out of orphan hearts. Svena:[confused] What are you talking about? The hearts of children without parents are no more magical than the hearts of any other child, which is to say not very magical at all. You know perfectly well that humans are a vastly inferior source for— Amelia: For the love of—it was a joke.
In the Heralds of Valdemar series, the worst and most potent forms of Blood Magic are powered by sacrifice. For every rule there is an exception; a good form of human sacrifice (albeit voluntary self-sacrifice) is practiced, rarely, by the leaders of the Shin'a'in tribes to call on their Goddess, basically to prove how truly dire the situation is and how much they need her help. And, as with the Dresden Files example above, mages can blow themselves up in a last-ditch desperation attack called Final Strike.
House of Hell have the titular house being owned by the Earl of Drumer, who runs a Religion of Evil called the Cult of Drumer who lures unsuspecting travelers into becoming sacrificial subjects for their various rituals.
The House of Night: Two in Awakened, Jack(!) and Zoey's mother Linda (very nearly Zoey's Grandma!), both sacrificed by Neferet.
The Hunger Games: Tributes are sacrificed by the Capitol to remember the betrayal of District 13.
In Andre Norton's Ice Crown, Roane once witnessed a ritual killing on another planet. A scene on Clio reminds her of it.
In The Iliad, Achilles captures twelve Trojan youths to sacrifice on his beloved Patrocles' funeral pyre.
Lammas Night has both sides getting involved with this. The Thulists in Germany routinely sacrifices people during their rituals, while the Oakbrook Manor coven in Britain expect a Heroic Sacrifice to be needed to protect the country (and their current High Priest has tagged himself for the role).
Generally averted in The Locked Tomb. Necromancy may be the Nine Houses' bread and butter, and violent death, particularily that of a child, releases a lot of Thanergetic energy, but the Empire still frowns upon killing someone just to gain power. The Reverend Mother and Father of the Ninth House, however, killed two hundred children, an entire generation, to ensure their daughter would be a powerful necromancer.
The Lost Years of Merlin: Fincayran humans sacrificed dwarves and other races in the past, as the absolute nadir of their misdeeds. It's this which caused Dagda to remove their wings.
Shirley Jackson's "The Lottery". The lottery is an early-summer affair to choose the victim of a ritual stoning, implied to be a harvest offering.
A Memoir by Lady Trent: Segulist Scripture claims that the Draconeans practiced this, and it was one of the reasons God allowed their civilization to be destroyed. Blackened pillars have been found at Draconean ruins, with some speculating they were for burning people alive. In Turning Darkness Into Light, Audrey and Kudshayn translate an ancient text that seems to confirm these suspicions. It turns out the last few tablets were a forgery by Fantastic Racists to stir up anti-Draconean sentiment ahead of a vote on Draconean sovereignty.
In A Memory Called Empire, the Teixcalaan empire is based on, among others, the Aztec, so of course they practice a fair bit. Human sacrifice is considered somewhat unusual in the modern age, but are still performed by volunteers (who usually do the deed themselves) for significant events. During Mahit's stay on Teixcalaan, she's witness so a supporter of the general One Lightning sacrificing himself in the hopes of giving One Lightning success in battle, and Emperor Six Direction sacrifices himself to legitimize his successor, and give her enough good PR to immediately end the Succession Crisis that was starting up. In a bit of Blue-and-Orange Morality, sacrifices are required by law to be volunteers not because it's inhumane to kill, but because picking out someone or taking someone random would take the chance of having that honor away from someone more dedicated.
Merkabah Rider: In "The Blood Libel", the Rider clashes with a Cult that is kidnapping children and sacrificing to the demon Moloch.
In Teresa Frohock's Miserere: An Autumn Tale, Lucien knows that Catarina will institute this once her plans are complete.
In The Night Mayor, the protagonists are trapped in a virtual reality realm built of old movie tropes. At one point, they're captured by an evil cult who try to sacrifice the female lead to their god.
Practiced by some of the cults on the Street of (the) Gods, which appears in a couple of Simon R. Green's Nightside novel series. It's widely regarded as unsavory, but it's not technically banned as long as it doesn't endanger the tourists.
No Gods for Drowning: Lilac Antonis has been ritualistically killing people in the city of Valentine as an offering to her mother, a goddess of blood. Lilac slices into the flesh of her victims and then uses the blood of her victims to draw symbols near them as a method to try and summon her mother, who she hopes can save Valentine from flood waters that are threatening to drag the entire city and its inhabitants under.
Obsidian & Blood takes place in the Aztec Triple Alliance at its height. As such, human sacrifice is quite prevalent. Interestingly, unlike other examples of this trope, the sacrifices are portrayed exactly as they would have been in the Triple Alliance: as a necessary and honorable sacrifice to keep the end of the world from coming. Since it's a fantasy novel, it really DOES keep the end of the world from arriving.
In The Obsidian Trilogy, the Endarkened perform sacrifices of sapient beings (not just humans) as a standard part of magical rituals. They plan to perform one ritual in particular at the climax which would release their God of Evil from his banishment, but it requires an unwilling sacrificial victim, and one of the main characters foils it by switching places with the victim at the last second and dying willingly.
A Nichts worshiping cult in Of Fear and Faith sacrifices people on a bloody altar in order to summon Nichts, ostensibly under their control. When Phenix finds them trying to do this to Elin, it doesn't end well for them.
Old Kingdom: The only way a Charter Stone can be broken is if a Charter Mage is sacrificed upon it. To break one of the six Great Charter Stones, only the blood of one of the Great Charter bloodlines — the royals, the Abhorsens, and the Clayr — will do. The Big Bad of Sabriel, a renegade member of the royal family, had his two sisters sacrificed to break two of the Great Stones, and would have broken two more with the blood of his mother and half-brother had the Abhorsen not arrived.
In John Milton's Paradise Lost, this is pointed up as a trait of Moloch, via burning little children alive.
First MOLOCH, horrid King besmear'd with blood Of human sacrifice, and parents tears, Though for the noyse of Drums and Timbrels loud Their childrens cries unheard, that past through fire To his grim Idol.
A renowned anthropologist in Pastwatch: The Redemption of Christopher Columbus by Orson Scott Card postulates that slavery — our heroes' motivation to meddle with the past in the first place — actually emerged as a relatively benign alternative to human sacrifice. (This is relevant because the Tlaxcaltecs, who never got that cultural meme, may well have taken over the world in another timeline.)
Tamora Pierce's standalone short story "Plain Magic" is about a teenage girl whose village stakes her out as a sacrifice to a dragon that's been terrorizing the area, on the advice of the local wizard. She's saved by a peddler woman who knows that this is unnecessary; apparently dragons in this world are ordinary if dangerous wild animals and the idea that they care about having virgins to eat is just a superstition.
In A Practical Guide to Evil some evil nations, such as Praes or Helike, practice human sacrifice to fuel magic rituals, such as making barren fields fertile or letting fortresses fly.
Noah from The Raven Cycle was sacrificed by his best friend in an attempt to wake up a ley line. It didn't work. Noah did, however, get to live on as a ghost due to the power of the place where he was killed.
In Ann Leckie's The Raven Tower, gods are empowered by faith and sacrifice; human sacrifice is the most potent, and a willing sacrifice is enough of a boost to make major miracles happen in return. Most willing sacrifices are worked out well in advance by contract, with the deity being obligated to provide a miracle in return for the death of one of its followers. The Raven's patronage of Iraden is bought with the regular self-sacrifice of its head of state.
The Reluctant King: Murugong demands human sacrifices by his worshippers. He isn't too choosy on just who his worshippers are, only that they provide this. Some magic also requires such a sacrifice, as related at the end of The Goblin King.
In Keith Laumer's Retief short story, "The Brass God", the Hoogan Pope wants to sacrifice the entire Terran diplomatic team for consorting with demons (actually another unrecognized alien species), but when it's pointed out that this might make the Terrans reluctant to keep funding his theocracy, he decides he'll be satisfied with sacrificing Retief alone.
Invoked in Roadside Picnic (as in its more famousadaptation): Getting to the center of the Zone allows for your wishes to be granted. However, there's a Meat Grinder anomaly blocking the only path. It'll go away for a few minutes if something is thrown into it — something large and organic...
The Saga of Hallfred Troublesome-Poet: On his journey to Vastergotland in Sweden (which, unlike Norway, is still pagan), Hallfred is seized under false accusations of murdering a farmer, and after convening to judge him, the locals decide to offer the stranger as a sacrifice. However, Hallfred's innocence is revealed before the sentence is carried out.
In James Herbert's Sepulchre, Felix Kline's custody of the preserved heart of Sumerian incarnate deity Bel-Marduk enables Kline to transfer the effects of bodily ageing onto others — a process which requires the slaughter of a human being, into whose departing life force Kline, via Cabalic recitation, attunes for absorption.
In The Saga of the Borderlands, by the Argentinean writer Liliana Bodoc, the empire of the Lords of the Sun performs human sacrifices, especially of virgin princesses, a practice that to other peoples of the Fertile Lands it seems repugnant.
In Shaman Blues, the hallmark of Black Magic are sacrifices, which eventually escalate into human ones. The villain is suspected of having performed those, as the heroes find twelve skeletons in her basement.
In Bernard Cornwell's Sharpe's Tiger, Tippo, though a Muslim, practices this. It saves Sharpe's life, and some other prisoners'; they are saved in case they are needed.
Simon Ark: In "The Mummy from the Sea", it is speculated that the Body of the Week was killed as a sacrifice to the goddess of the sea. In reality, the killer dressed the body up to look like a sacrifice to disguise the actual time and cause of death.
At the end of the first book, Daenerys burns a woman alive in order to produce a fire capable of hatching her dragon eggs. To be fair, the woman in question was pretty nasty and would almost certainly have been executed one way or another.
The followers of the Red God, R'hllor, are fond of burning people. Melisandre in particular is searching for "King's blood" (a King or his children) to burn, since sacrificing royals apparently provides more power than sacrificing common men.
The Iron Islanders drown victims for the Drowned God. Now that Victarion Greyjoy serves both R'hllor and the Drowned God, he burns a ship of captured women at sea for both gods.
This seems to have been a fairly integral part of how the Old Gods were worshipped in the North, once. At one point, Brandon has a vision of ancient Starks slitting a captive's throat in front of Winterfell's heart tree. At another point, a character tells of a historical incident where a band of slavers were captured by Northern soldiers and given over to their slaves, who tore them limb from limb and hung their entrails on a weirwood's branches to honor the gods.
In Lois McMaster Bujold's Historical Fantasy novel The Spirit Ring, the creation of any of the spirit rings of the title in a sense involves this trope, since the power of such rings comes from binding the spirit of a dead person to the ring. The creation of one such ring is planned to involve an additional human sacrifice, the ritual slaying of the brother of the man whose spirit is to be thus bound, which the necromancer in question calculates will be especially efficacious in completing the ritual.
Star Wars Legends: The Yuuzhan Vong in the New Jedi Order series will happily sacrifice humans (and other sapient beings) on a grand scale as part of their worship. Notably, they have the same basic reason as the real-world societies that inspired them, such as the Aztecs — they believe that such offerings are necessary to sustain their gods, without whom the universe could not exist. Of course, the Vong themselves have little to no fear of death or pain, so they don't really have the context to understand why everyone else thinks they're so horrible.
In Poul Anderson's Three Hearts and Three Lions, a water spirit reveals she has no soul by her idle comments about the human sacrifices that a barbarian tribe offers her annually; she says only that it's not that useful because she's not a cannibal, but they do wear nice clothing.
Time Machine Series: Quest for King Arthur has the protagonist captured by druids at one point for a sacrifice. In Quest for the Cities of Gold from the same series, he is captured by Aztec priests.
The Fall of Númenor: After the Númenoreans have been converted to Morgoth worship, they build a huge temple where kidnapped non-Númenoreans, as well as Númenoreans who remain faithful to Eru and the Valar, are sacrificed by Sauron to Morgoth with the goal of preventing their deaths (unaware that death is inevitable, and even if it was within his power, Morgoth would never spare them from it).
The Lord of the Rings: Throughout the Second and Third ages, Sauron also gets the Easterlings and Haradrim under his rule to worship him in such a way.
The Tough Guide to Fantasyland: Evil religions and magic-users both tend to practice this, specifically of virgins most often though of other people too. The sacrifice being disemboweled, raped and or mutilated in some other way precedes this quite often. The characters will arrive either shortly before or just during the event, allowing them to interrupt it before any of the worst of it can happen, or long after the fact, in which case they can do little beyond burying the piteous body.
The Traveler's Gate: Damasca takes nine citizens every year to sacrifice to the Hanging Trees of Ragnarus, which keep the Incarnations sealed. The series starts with Damascan soldiers wandering into Myria, a tiny village that isn't even aware they are part of Damasca and has no idea anything is expected of them. Apparently the soldiers are not normally supposed to take all the sacrifices from a single village, especially not such a small one. It's not clear why it was done differently in this case.
In The Vampire Lestat, Marius tells the story of how Druids would kidnap the right kind of man, train him, and then sacrifice him to the god of the groves. Which turns out to be a vampire who will make him a vampire for the Druids to worship.
The post-apocalyptic Mexican regime in Victoria explicitly imitate their Aztec ancestors and follow a cannibalistic Religion of Evil loosely based on pre-Columbian paganism. Human sacrifice is also practiced on a lesser scale by the neo-pagans in Cascadia, once their leaders go full Axe-Crazy.
In Dan Abnett's Brothers of the Snake, one Iron Snake is captured, and they find him after he has nearly been tortured to death by cultists to summon a daemon.
In Dan Abnett’s Ravenor Returned, the ritual to awaken the daemonic Brass Thief requires sacrificial offerings to be caged up within the magic circle, so that the daemon can slaughter them when it manifests. Only then will it be willing to obey the summoner’s commands.
In Valentin Ivashchenko's Warrior and Mage (Воин и маг, Валентин Иващенко):
Upon stumbling on a group of tomb raiders who have unleashed an epidemic curse from the tomb, Vale sacrifices the surviving raider to stop the epidemy. This is legal in the Empire.
During his Revenge crusade against the church, Vale executes the clerics from the chorus which destroyed his hometown by sacrificing them, causing his own men to slap some sense back into him. Although the clerics burned their families as well, they consider Vale's actions beyond justification.
In Vitaliy Zykov's Way Home (Дорога Домой, Виталий Зыков):
The kidnapped humans manage to botch up the sacrifice and survive, setting the plot in motion.
Necromancers of Nekrond will sacrifice whatever sentient needed for the current task.
K'irsan developed a ritual to fend off death by sacrificing another sentient to extend his lifespan. He is forced to go through said ritual sacrificing an elf. While this merely adds to the long list of reasons the light elves want him dead, the dark elf investigator on the scene is less than pleased.
Anything connected to the Elder powers will also require sacrifices. In a large-scale example, a minor ritual is used to trigger a monster invasion of a town. The dead of the invasion, numbering in the tens of thousands, are the actual sacrifice.
Being the victim of sacrifice was Turtle Heart's fate in Wicked. There was a major drought at Colwen Grounds. A rowdy crowd, incited by a prophecy-giving clock, killed him. His two lovers, Melena and Frexspar, never went back to Colwen Grounds afterwards. They instead became missionaries at Turtle Heart's home region.
The Witch of Knightcharm: The rookie witch Carlita Xique is said to be an expert on this. It's indicated that she's descended from a Mayincatec priestess and this this knowledge has been passed down within her family for a while.
In Young Wizards, a wizard can sacrifice himself by saying a certain short phrase in the Language of Magic, releasing all of his supernatural energy for use by the Powers That Be. This is an extreme measure, as in a series where Heroic Sacrifice is commonplace this is only mentioned in passing.
