The Power of Blood

"For the soul of every sort of flesh is its blood by the soul in it. Consequently I said to the sons of Israel: 'You must not eat the blood of any sort of flesh, because the soul of every sort of flesh is its blood. Anyone eating it will be cut off.'"

— God, Leviticus 17:14, The Bible

Blood. Animals have it, humans have it, even aliens have it. There's just something about the red liquid that flows through our veins that makes it seem important. Probably something to do with that whole "keeping us alive" thing it does so well. As such, in fiction, it tends to have one or more of these properties.

• A) Blood is binding — Any Magically Binding Contracts made in blood must be honored, on pain of death, even if the contract was only written in blood because you Couldn't Find a Pen. If you make a Blood Oath, and swear that "if you break your word, may the earth drink your blood!", and break your word anyway, you may find yourself six feet under. And finally, blood is most definitely Thicker Than Water, so kinship can be exploited for any number of magical effects.

• B) Blood is symbolic — Blood may be used as a stand-in, or weaker form of souls, life force, what have you. Alternatively, other things may be used to symbolize it. The latter applies to things like an android's oil being sprayed out like it's High-Pressure Blood (for examples of the latter, see Machine Blood).

• AB) Blood is magical — Any spells that require blood as a reagent will probably be either extremely powerful, Black Magic, or both. Since blood is basically Life Energy, anything using it will work similarly to things Cast from Hit Points, or it may be used to create life. The blood of especially powerful or arcane creatures may compel others, heal, grant immortality, or even become gems or weapons. See also Blood Bath.

• O) Most importantly, Blood is disturbing — There's just something about blood leaving the body that generally freaks people out, either from fear or disgust. For obvious reasons, it's directly associated with pain, injury and death. Horror and Slasher stories rely on this. A further division of this, often connected to A, B, or AB, are messages written in blood, which are used primarily to scare the bejeezus out of people, but may also have magical, symbolic, or binding properties. This is sometimes combined with Room Full of Crazy for the extra creepy. Properly used, blood can turn fear into Primal Fear — as per the shower scene in Psycho: the sight of Janet Leigh's hand trailing slowly down the shower curtain — scary. The blood (actually just chocolate syrup) smearing under her fingers — PSYCHO! Some movies overdo this though, resulting in mere Squick.

Now, remember: Type AB Blood Power draws off of all the others, and all of them draw from Type O. Just be aware of the donor; may contain Bloody Hilarity. Has nothing to do with The Power of Cheese. For the more real-life version, see Blood Transfusion Plot.

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Examples:

Type A

Anime & Manga

• It's explicitly said in Chrono Crusade that when Chrono made a contract with Mary Magdalene, his first contractor, that she had to give him some of her blood to complete it. It's implied (using vampire imagery) that this was also the case with his contract with Rosette.
• Eureka Seven: coming of age rite to calm the planet, ISN'T NICE
• In Naruto, to summon animals one must first sign a summoning contract. It requires that the user must sign it in his/her name in their own blood followed by a fingerprint stamp in blood as well.
• The ultimate use of her power to unite humanity into a single being, Charlotte B. Lord of Unlimited Fafnir can use massive amounts of her own blood to control other people over a wide area, with the controlled adding their blood to the equation in a positive feedback loop that could involve the entirety of humanity.

Fan Works

• A Growing Affection has a Blood Oath Jutsu, which is absolutely binding. Whatever a person sets as the penalty for breaking the oath, his or her own body and chakra will make happen.

Film

• Being 'blood brothers' is part of many westerns.
• Apostle: The cult of the island has been trying to keep the island going by sacrificing their blood to the island's goddess. This turns out to be the disturbing sort, as feeding blood to the goddess, rather than just worshiping it, causes it to pervert itself into a Humanoid Abomination that has been slowly killing everything in the island.
• In the film Mongol, young Temudgin makes a blood oath with Jamukha, who saved his life. This makes Jamukha the brother to Temudgin, and in the end, Temudgin lets Jamukha go, even though he proves to be a threat in the future, saying that he's not sparing an enemy, he's freeing his brother.
• In Pirates of the Caribbean: The Curse of the Black Pearl, the blood of those who took coins from the Chest of Cortez (or that of their children)is required in order to end the curse.
• Being deemed negro was an important plot point in Show Boat. By sharing a drop of blood, the hero was now deemed negro and could marry his sweetheart without violating the miscegenation laws. Note that this wasn't, strictly speaking, either a legal or magic thing: his sweetheart was mulatto (half-black, half-white). He cut her finger and sucked out a drop of blood so that he (and the people who witnessed it) could say that he "had negro blood in him" without actually lying.

Literature

• Marie Brennan's Doppelgänger duology features a blood-oath as a plot point in both books. If the oath is broken, the magically-sealed scar will bleed the Hunter (or witch or Cousin in the second book) to death through one wrist. Unique in that the oath binds both parties to their word (presumably; the actual wording states that the contractor binds him/herself to grant the contractee three boons without conditions, so magical compulsion may or may not extend to the contractor). Also a slight crossover with Type AB, as blood is used not only to bind the contractee, but as an elemental focus for shaping the complicated spell, and while it represents Fire in the blood-oath spell, it is "one of the rare foci that can serve for more than one."
• The hundred gods in Godslayer Chronicles by James Clemens, AKA James Rollins, in contrast with the rogue gods, became the hundred by binding themselves to the land. This was done by spilling massive amounts of their own blood upon the ground. The act purged them of the insanity of the rogue gods, but forever confined them to an area within an unspecified radius of where they spilled their blood. Any god that leaves its realm or enters another's realm (including rogue gods entering a realm of the hundred) bursts into flames and dies.
• Tortall Universe: In the Trickster's Duet, an oath sworn in blood kills anyone who breaks it, with the blood boiling in their veins. It's not much favored in Tortall due to the nastiness of it, but Aly happily exploits it when forcibly recruiting spies from the enemy in the Copper Isles.

Live-Action TV

• Kolchak: The Night Stalker. In the episode "The Devil's Platform", a politician makes a Deal with the Devil to obtain power. He offers Kolchak the chance to do the same thing, and tells him that he will need to sign his name in blood.

Mythology & Religion

• In The Bible, the covenants that God makes with His people (which include the Mosaic Covenant and the New Covenant) require the shedding of blood in order to be effective and binding.

Tabletop Games

• In both Vampire: The Masquerade and Vampire: The Requiem, vampire blood is highly addictive to both vampires and mortals. The eponymous Blood Bond is formed when someone drinks three times from the same Vampire within a period of time, and forms such an intensely emotional and psychological bond in the drinker that it becomes difficult for them to willfully do anything which could cause even distress or disappointment in the host vampire.
• Warhammer 40,000:
  • The Grey Knights keep a massive library containing the true names of daemons, each written in an Imperial servant's blood one syllable at a time per copyist to prevent the daemon from having power over the book it's kept in.
  • Ironically, Khorne the Blood God is a War God who despises magic users as cowards, thus magical blood is averted for his troops. They do sometimes use pools of blood to summon deamons, though.

Theatre

• Averted in Damn Yankees, where Applegate laughs at the idea of having Joe sign his name in blood to the contract.

Web Comics

• In Homestuck, Sburb's Blood aspect is introduced with the troll Karkat, the Knight of Blood. Despite the name suggesting a specially vicious fighter, it refers to his role as Team Mom.
  • Taken even further with his ancestor The Sufferer, who was the Seer of Blood in troll's Universe previous iteration.
  • Inverted in that blood color in troll society determines the caste, thus causing division.
• In Sluggy Freelance only Gwynn can use the Book of E-Ville to cast spells because her name has appeared on the inside cover written in blood. Right above instructions to, if lost, drop in any mailbox to return it to the rightful owner.

Web Original

• Whateley Universe example: Carmilla and Fey made a blood pact that was so powerful it gave them some of the other's traits. Carmilla now has Fey's body (including Pointy Ears) and hair, and Fey got some of Carmilla's mental capacity.

Other

• The idiom "blood is thicker than water". Exactly what this means has had a few different definitions over the centuries, but the binding aspect is always clear.

Type B

Anime & Manga

• In Fullmetal Alchemist, Ed and Al use drops of their blood to stand in for "information of the soul" when trying to bring back their mother from the dead using alchemy. It was later revealed that this didn't work. When they later dug up and examined the remains of the failed body that they created, they found that it had features that their mother didn't have and also wasn't even female. And further proving that their mother's soul was never in the body they made, Al regained memories of what happened and remembered that he was actually the soul inside of the body for the short time it was alive. Philosopher's Stones also comes in various forms. Solid, liquid, they're all blood red.

Literature

• In the Sword of Shadows series, blood is sacred to the Sull, who bleed themselves as a form of offering to their gods. Obviously, most Sull become very skilled at letting blood with minimum pain and without hitting anything important.
• Sunshine: Blood nourishes vampires because it represents the victim giving up part of themselves, and only when the victim consents (however unwillingly) to them drinking it. Oddly enough, this means that vampires can also get some nourishment from tears.

Tabletop Games

• One of the Liminal Exalted castes is blood. Given that the Liminals are basically reanimated corpses, this is quite fitting.
  John Morke: Aspects of Blood are born of creators driven by “possessive” passion—lust, greed, and ambition. Blood represents the heat of passion and the wonder of emotion. Blood is a carrier as well as a fulcrum; it can be a river of plagues or a font of virginal purity with which to attract and bind the foulest of horrors and bid them whip. Blood Aspects are sanguine, passionate, outgoing creatures.
  Blood Aspect magic, for example, may allow a Liminal to easily track a man for hundreds of miles with only a sample of bodily fluids to work from, but it also allows confident navigation of the dark waterways and torrential courses of the Underworld, as well as influence over the desires and addictions of others.
• Mage: The Awakening: Due to its symbolic associations, fresh blood has several uses in Life magic. It can substitute for a personally dedicated magical tool (like a ceremonial wand), insulating the spell against Magic Misfire, and serve as an Eye of Newt to perform Ritual Magic.
• In an extension to the Vampire: The Masquerade example above, the Kuei-Jin, the Asian equivalent to Vampires, live on life-force. The weaker ones drink blood simply because that's the easiest way to get at somebody's life-force. The stronger ones can straight-up eat your soul.
  • Notably, western vampires have a derangement called Sanguinary Animism that makes them think they do the same thing as the Kuei-Jin. Sufferers hear the voices of people they've drunk from in their heads, and believe that if they ever drink a mortal to death they also consume their soul. This essentially causes the vampire to suffer from Split Personality (and not the fun kind) when they drink blood.
  • When it comes to Thaumaturgists, the basic in-universe mechanics of the art requires both Paths and Rituals to have some way to "target" the subject of the power. With most Paths, it's as easy as being near enough to see the target. With rituals - which could take minutes, hours, or even days of preparation - there's got to be something on hand to establish what — or more importantly who — the magi is going after. And there's nothing that ensures a target lock like having a sample of the victim's blood. Except maybe knowing the victims True Name, but that's difficult to learn.
• Warhammer 40,000: One of the main tenets of the Khornate religion (BLOOD FOR THE BLOOD GOD! SKULLS FOR THE SKULL THRONE!) is that their god demands blood, no matter whose, as long as it's obtained through combat.

Web Comics

• In A-gnosis' comics on Greek myth, ghosts can drink blood offerings to strengthen their link to their old lives for a short time. This helps one ghost in Nekyia overcome her Ghost Amnesia and another in Daddy's Girl communicate with the living.
• Kill Six Billion Demons: Devils enter pacts with mortals to feed on some of the mortal's Soul Power and stabilize their own chaotic spirits. Those who don't want to be bound can get the same benefit from human blood and flesh.

Type AB

Anime & Manga

• In Black Cat, Sheldon's Tao is manipulating blood.
• Blue Ramun: The blood of members of the Blue Ramun tribe possesses an incredible innate healing ability, and is described in-story as one of the most powerful forms of magic in the Low Fantasy setting. Even diluted into herbal poultices or enteral medications it can cure most poisons, speed the healing of otherwise fatal wounds, and almost completely reverse the effects of diseases like anemia.
• One of the Contractors in Darker than Black, Wei, is able to teleport away anything that is covered in his blood. This power is frequently used to create gaping holes in the torsos of his enemies. Naturally, the only way he can use this power is by carrying a knife and cutting his own wrists to toss blood on opponents. In case you couldn't tell, he's a bad guy.
• The entire combat system is Deadman Wonderland is based around the titular Deadmen using their blood as weapons in various ways.
• In Fullmetal Alchemist, Ed uses his blood to draw the alchemical seal which binds Al's soul to the suit of armor. Apparently, being produced in a living body and rich in iron makes blood a good intermediary between souls and steel.
• Hellsing, where it has slight crossover with Type B when referred to as "the currency of the soul." What it means is that vampires like Alucard absorbs their meals' souls when they consume their blood. Seras discovers this truth when she consumes Pip's blood, collecting his soul, becoming a true vampire, and herself gaining some of the Power of Blood. Later, it's revealed that the huge amount of souls he's consumed fuels his absurdly powerful Healing Factor — and that he can release his victims as a macabre army of the undead.
• The jousei manga It's Not Like That, Darling uses a more passive form of this trope (a combination of Type B and Type AB). The main character gets a blood transfusion after an accident in the backstory. Later, the donor dies in another, unrelated accident and our heroine finds herself having the strangest thoughts... A tolerably good romantic comedy, as such things go.
• JoJo's Bizarre Adventure: The stone mask introduced in Phantom Blood emit sharp joints upon receiving a single drop of blood that impales whoever is wearing it to turn them into a vampire. After becoming one himself, Dio Brando is able to use his own blood to transform others into his vampiric servants, and as seen in Stardust Crusaders, also use his blood to revitalize complete fatal wounds.
• In Rumiko Takahashi's Mermaid Saga, mermaid flesh can, if you're (un)lucky enough to survive eating it without becoming a Lost Soul, turn you immortal. But in the "Mermaid Forest" story, all that Sawa has is a flask of mermaid blood to heal her sister's illness. It made Towa immortal, but deformed her arm like a Lost Soul's, and now she regularly replaces it with arms cut from the fresh corpses of young women.
  • Referenced in Hell Teacher Nube. Here, flesh from the (still living) mermaid Hayame has a 100% success rate, and her blood can instantly heal any injury no matter how grave, without conferring immortality. It does have the side effect of making the recipient into a moron for a short while, seeing as it comes from Hayame, after all.
• In Negima! Magister Negi Magi, Evangeline, who was de-powered into being stuck on the school's campus by Nagi the Thousand Master says an ample (probably fatal) drinking of blood from him or one of his relations will somehow lift the curse.
  • It's stated (at least in the English translation) that an alternate method of executing a Pactio is "open veins, swap blood", but that's not as Fanservice-y as kissing, so it's never actually been done that way.
  • Even later, Negi learns a spell that requires him to bleed before he can use it, although that may be only in it's incomplete form. He uses the full version later and doesn't bother with the blood.
• In Princess Tutu, Drosselmeyer wrote a story in his own blood to control the town where the anime takes place.
  • Also, the Raven is so evil that his blood can turn people evil when they ingest it, bathe in it, or have it otherwise go into their body.
• Welcome to Demon School! Iruma-kun: Iruma finds that human blood has strong magical properties in the Demon World. He accidentally heals a giant bird with a drop of his own blood, and much later uses another drop to nurture a vine plant: it grows to titanic size and causes tremors across the entire forest Iruma was in at the time.

Comic Books

• In Detective Comics #833 Zatanna is shot in the throat by the Joker and dunked into a tank filling with water, effectively keeping her from reciting her incantations backwards. When Batman escapes his own deathtrap to free her in #834, he finds her throat completely healed. Upon inspection, Bats discovered she'd used her own blood to write "HEAL ME" backwards on the inside of the tank's lid.
  Batman: A spell written in blood. For a mage like Zatanna, no enchantment is more powerful.
• Another parody happens in Lenore the Cute Little Dead Girl, when she pricks her finger and spills a drop of blood on a doll. It turns out to be a vampire that was cursed to be an inanimate plaything, and her blood broke the curse. Unfortunately, he realizes he's still in a doll's body because the curse didn't break properly; she'd been embalmed.
• In The Sandman: A Game of You, menstrual blood is used to power a spell to send the characters to the land of the dead and come back alive (mostly). In The Time of Your Life, the same spell is powered from blood from Foxglove's hand.

Fan Works

• The A Song of Ice and Fire fanfic blood of my blood depicts a fairly straightforward Blood Transfusion Plot between the Lannister twins, with Cersei as the donor and Jaime as the patient. The procedure is performed by Qyburn, a man who is both a doctor and a necromancer. Given the setting, it's framed as quasi-magical, in the same way that the Ironborn view CPR as a religious rite to the Drowned God. The fic frames blood as heavily symbolic in general. The whole thing is seen as the inverse of amputation—something being added, rather than cut away. But also, blood is magical, in that it has the power to do this. Cersei compares it to what Maggy the Frog did with her blood. And blood is binding, Cersei imagining the procedure "binding them anew."
• The Chaotic Masters: The Collector can only be freed from the Magic Mirror he's trapped in if it's exposed to the blood of someone else "born from the stars", i.e. an alien.
• Child of the Storm and its sequel, Ghosts of the Past, draw on both Harry Potter and The Dresden Files, particularly the latter, in their use of blood magic. While it isn't necessarily dark magic, and can be used benevolently to enhance spells, empower rituals and magic circles, and enforce bindings, it does stray very close to that area, and is much favoured by vampires - especially the Red Court and, to a lesser extent, Dracula's Grey Court. As a consequence of the latter, Doctor Strange has Harry study up on it extensively when he's set to run into Dracula and his plan to use the blood of a Super-Soldier to become, among other things, immune to sunlight.
• A Growing Affection: Naruto's Blood Clone Jutsu, a dangerous technique that uses blood to create stronger clones.
• The Night Unfurls: This trope is present due to being a Bloodborne fic. Kyril's Blood Vials can heal any ailment. Moreover, Kyril's Alien Blood, Blood Gems and Blood Stones (the latter two used for enhancing trick weaponry) are responsible for enhancing the apprentice hunters' combat capabilities. In particular, Hugh's Chikage has a blood rite with a Cast from Hit Points ability, feeding on the blood of both the user and anyone on the receiving end of the blade.
• In The Wisdom Seeker- the sequel to The Secret Keeper- when the Cullens drink dragon’s blood in the Leaky Cauldron, it not only completely removes their usual thirst to such a degree that Edward doesn’t even feel slightly tempted by Bella’s blood when she's right next to him, but the blood also restores their original eye colour from when they were human for at least the next few hours.

Film

• The Golden Voyage of Sinbad. The wizard Prince Koura uses his own blood to create a homunculus.
• Ryuhei Kitamura's Versus revolves around the "Blood of Resurrection," which the villain plans to use in the Forest of Resurrection to open some kind of a dark door and get "The Power." Zombies and reincarnated samurai are involved.
• The blood of those who took the coins from the Chest of Cortez is required to lift the curse in Pirates of the Caribbean: The Curse of the Black Pearl.
• In Puppet Master Vs Demonic Toys, a small blood sacrifice is needed to bring the toys to life. Leading to some Hypocritical Humor when the two heroes wonder what sort of sick person would use such magic before discussing which of them should provide the drop of blood.

Literature

• In The Chronicles of Amber series, the mystic Pattern that created the universe was drawn in the blood of its creator. The discovery that the blood of his descendants could erase it drives part of the plot.
• Some cross-over with Type A in the Chronicles of the Kencyrath with blood-binders- Kencyr who have the inherent magical ability of creating a telepathic link with anyone who's exposed to their blood, a link that is so powerful that can endure past death. Darkling Changers have a related ability of being able to take the form of anyone whose blood they've sampled. If a Changer tries to feed on a blood-binder, and the blood-binder's magic is stronger, then the Changer will be wracked by intense pain, the only known release form which is death.
• In one of Tamora Pierce's Circle of Magic books, Niko cuts his palm so that he can use his own blood to fuel a past-viewing spell, saying that mages will often use blood to make a spell more powerful. He then says some use their own, others use the blood of others — willing or not — and sternly warns the student listening to him not to use others.
• In the Codex Alera series, the Alerans have magical creatures living inside them that give them elemental magic powers. The werewolf-like Canim don't have inherent magic like that. So they drain blood from freshly dead sentient beings, and use that to cast magic. The magic is appropriately creepy, and destructive. One creates clouds of acidic mist, another summons tentacled horrors from midair which are also acidic or at least venomous, and a third calls down lightning on chosen targets. All of these require the spilling of blood. However, it is stated that ritualists are also their peoples' priests and doctors, so presumably they have more benign spells that we don't see because we only see them during battles. In addition, some Canim use the blood of their enemies to fuel spells and sometimes kill civilians specifically for their blood, but more noble ritualists only use blood from volunteers or their own.
  • On the 'Night of Red Stars', the Canim ritualists cast a spell that puts acid mist clouds full of weird seemingly extradimensional tentacle monsters over a good part of the continent, preventing the Alerans from flying (since they get eaten/dissolved if they try to go through the clouds). But this huge spell is said to cost millions of Canim lives.
• Cursed World: Ella the sanquinmancer can read "the chaos in blood" to get a read on someone, alluding to Type B, but their reluctantly used true power is that by drinking blood their senses and attributes are magnified many times over... at the cost of gaining a craving for even more blood.
• The Daevabad Trilogy: Daeva society was once ruled by the Nahid Dynasty, descended from the one daeva to win the trust of the Prophet Suleiman. Their blood is unique in that it's a deadly poison to the ifrit — those daeva who defied Suleiman at the cost of their magic.
• Discworld parodies this with the Rite of Ashk'Ente, which summons Death - it's implied that this is supposed to require a human sacrifice, but magical refinements mean that it's now possible with only "4 cubic centimetres of mouse blood".
  • In Carpe Jugulum, Granny Weatherwax uses this kind of blood magic against vampires by 'infecting' them when they feed on her.
    I aten't been vampired. You've been Weatherwaxed.
• The Dresden Files has this trope down to a science. Blood can power rituals, keep curses alive through generations, fuels Red Court Vampires, can be used to track someone or otherwise create a symbolic link to them on which to do magic.
• The Elenium plays with type AB. In this case blood isn't so much magical as it is innately capable of restraining magic. The living stone Bhelliom is supposedly controllable by two rings, each of which contains pieces of the original Bhelliom stained red with blood. Later, it's revealed that blood restrains Bhelliom for a very prosaic reason: Bhelliom cannot stand the touch of iron, and human blood has iron in it.
• In the Godslayer Chronicles by James Clemens, AKA James Rollins there are 9 bodily fluids^note Blood, Sweat, Tears, Saliva, Phlegm, Semen, Menstrual Fluid, Shit, and Piss or "humors" that are given by the gods, which hold the god's powers and are combined in various ratios to produce magic. The one rule to mixing is that blood must always be present, it functions as the activator and no magic can exist without it. Therefore it is also the most sacred and closely guarded of the humors.
• In Harry Potter and the Goblet of Fire, Voldemort uses Harry's blood to reconstitute himself. In addition to reviving himself, it gives Voldemort the power to touch Harry, because the all-sacrificing love that Lily imparted to her son resided in Harry's blood. This later backfired as the blood link to the then-immortal Voldemort prevented Harry from dying, though this didn't stop a rebounding Killing Curse later on.
  • And speaking of Lily, the fact that Harry lives with her last blood relative (her sister Petunia) allows Dumbledore to cast a protective charm that makes Number 4, Privet Drive (Petunia's home) the one place where Voldemort and his mooks cannot get close to Harry.
  • Also, in Harry Potter and the Half-Blood Prince, a small blood sacrifice is needed to reach the spot of Voldemort's Horcrux. Dumbledore actually expresses disappointment at Tom Riddle for such a basic idea (that overlaps with Blood Is Scary, below), and points out to Harry that the idea is to weaken the intruder as much as possible.
  • And then there's unicorn blood. It will, according to Firenze, "keep you alive, even if you are at the brink of death, but at a terrible price. You have slain something pure and defenseless to save yourself, so you will have but a half-life, a cursed life, from the moment the blood touches your lips."
• Mercedes Lackey loves this concept, and blood mages are frequently villains in her books. Combines with Type O, since the shedding of blood is incidental — the suffering and trauma of the victim is the real source of power.
  • There are also good people who use blood magic — they only use their own blood. Most notably, the Shin'a'in, whose patron goddess will sometimes require someone (usually a shaman) to sacrifice themselves to prove the people's need.
• In New Arcana, only people with mageblood can use arcane magic, and mageblood is a street drug. The Order's soul-binding ritual involves mingling the blood of the cohort members.
• In the Old Kingdom trilogy by Garth Nix, the power of the Charter that gives the King, Abhorsen, and Clayr their unique abilities is found In the Blood — as in, both genetically and literally. Charter Stones, which keep the magical Old Kingdom sustained, can be broken if a Charter Mage's blood is spilled on them (in death), and the Great Stones can only be broken by the blood of one of the Charter bloodlines (see above.) Finally, in Abhorsen, Sam makes a sword to break apart the Eldritch Abomination by combining, among other ingredients, blood from carriers of all three four bloodlines.
• In Pact, blood is symbolic of the self, and can therefore be used as a source of power in an emergency-but only the mad or the desperate do this, because spilling blood is spilling the self, and a lot of Others like it when people are hollowed out shells-it gives them room to move in.
• In Shadows for Silence in the Forests of Hell, by Brandon Sanderson, shedding blood in anger will draw the wrath of the shades like nothing else. An accidental bump or nosebleed doesn't count, but blood shed in anger, exposed to the air, will enrage every shade in the vicinity. First, they will hunt down and kill whoever shed the blood, then, being enraged, they'll kill anyone else that happens to be nearby.
• The Mosquito-kinden of Shadows of the Apt have a serious thing about blood, and huge quantities turn up in some prophecies.
• A Song of Ice and Fire:
  • Melisandre uses the blood of a king in a ritual to cause the deaths of Robb Stark, Joffrey Baratheon, and Balon GreyJoy. Possibly.
  • The maegi Mirri Maz Duur also uses blood magic to "heal" Drogo and the favor is returned by Daenerys when she burns the maegi alive as part of the magic to awaken her dragons. Like Melisandre, Mirri Maz Duur also trained in Asshai.
  • Maggy the Frog—also a maegi from Essos, although not trained in Asshai—uses blood to tell Cersei's future.
  • Blood was also part of the Targaryens' reasoning for their rampant incest.
• In Stardust, the witches use the hearts of living stars to prolong their youth as a form of blood magic.
• Also from Sword of Shadows, it's possible for weaker sorcerers to enhance their powers by draining blood from a properly bound stronger sorcerer. Penthero Iss demonstrates both the binding and the bloodletting in Nightmare Fuel detail.
• In The Wheel of Time series by Robert Jordan, we have the mindtrap; similar to a phylactery. Combined with the blood and saliva of a channeler(magic user), it captures the soul, or essence of said channeler. Should this fragile item be crushed in someone's hand, the holder will have complete control over the (now)mindless puppet.
• In The Witchlands, Bloodwitches can distinguish people by the smell of their blood and track them down by it even across open sea. They can also control blood in other people's veins, letting them, for example, freeze them in place or stop their hearts.

Live-Action TV

• Buffyverse:
  • Seeing as it provided a title quote it's not surprising that Buffy the Vampire Slayer has a few examples of this. The blood of a slayer apparently has mystical qualities, allowing Angel to survive Faith's poison, and granting the Master the strength to escape his prison in the first season. Dawn's blood was used by Glory to open the interdimensional portal.
  • Angel also used this quite extensively. The Beast dripped blood onto the artifacts it had gathered as the final part of its ritual to blot out the sun. The blood of a virgin was used to expedite the birth of Jasmine. Lorne's blood was used in another ritual calling for the blood of a demon. And of course Hamilton's blood turned out to be full of the power of the Senior Partners, which led to a bad moment for him when he proceeded to boast about it in front of Angel, a vampire. There are probably a lot more. Any show with vampires and magic is likely to feature a lot of this trope.
  • In the episode "The Gift", Spike basically lays out the trope.
  Xander: Why blood? Why Dawn's blood? I mean, why couldn't it be like a, a lymph ritual?
  Spike: 'Cause it's always got to be blood.
  Xander: We're not actually discussing dinner right now.
  Spike: Blood is life, lackbrain. Why do you think we eat it? It's what keeps you going. Makes you warm. Makes you hard. Makes you other than dead. Course it's her blood.
• Doctor Who: In "The Christmas Invasion", the Sycorax use samples of A Positive that they took out of a satellite to control everyone in the world of that blood type.

Religion

• As Richard Carrier memorably put it: "God needed blood to fix the universe, but only his own blood had enough magic so he gave himself a body and killed it".

Tabletop Games

• The Whateley Family in Deadlands have this as their hat. It is Cast from Hit Points, is powerful and overuse does Very Bad Things. The Whateleys are for the most part inbred, insane, powerful, rich and servants of the Big Bad.
• Dungeons & Dragons: One of the material components for the Cacodemon spell (which summoned a powerful demon) was a bowl of mammal blood, preferably human.
  • Bloodpunk - A Guide to Tolia, a recent 3rd-party setting for Dungeons & Dragons, blood is the catalyst for a magic crystal known as Angst to produce light and energy. Now blood engines are used to power zepplins, trains, weapons and other technology, bringing the setting to about the Victorian period. Even before this, blood was venerated and used in just about every religion and school of magic.
  • In-character folklore (well, one version of it) of the default D&D pantheon holds that elves and orcs were born from the blood of their respective creator-deities, Corellon and Gruumsh, which got spattered across multiple worlds when their deities were fighting a death-duel (both survived, however).
• Exalted uses this trope in several places. Lunar Exalted gain their myriad of forms to pick from by hunting the creatures they seek and drinking their heart's blood; Abyssal Exalts can recharge their power by drinking blood; and several sorcerous (and all necromantic) rituals also require the sacrifice of blood in the process of casting. Sometimes from the caster him/herself.
• In Legend of the Five Rings, "Bloodspeakers" practice a very evil type of magic, powered by blood that is usually (though not always) unwillingly donated by others, who typically don't survive the experience.
• Common in the Ravenloft setting, both as a power-source for certain kinds of evil magic and as a means for vampires to bequeath temporary vigor and prolonged life to their mortal minions.
• In Rifts and the Palladium universe, blood sacrifices are common for most kinds of magic because P.P.E. doubles at the time of death. But the actual representatives of this trope are Blood Shamans, who cast grisly spells from their own blood with a bit of Casting from HP.
• In the Shadowrun supplement Aztlan, mages can use Blood Magic: spilling a human's blood to enhance spellcasting and summon Blood Spirits. Extremely evil, restricted to Non Player Characters.
• As mentioned above, both Vampire games take full advantage of this subtrope. Once blood enters a vampire's body, it becomes something more than blood (often referred to by vampires as "Vitae").

Video Games

• ANNO: Mutationem: A research document located at The Consortium's underground facility details that each of the seven subjects of The Gatekeeper Project were infused with a classified blood type that gave each of them a inherent dimensional ability.
• Blood is a central part of the lore and mechanics of Bloodborne (as the name implies). Your character can use Blood Magic, uses blood vials to level up and heal, and originally came to Yharnam to treat some ailment with the Blood Ministration that Yharnam's primary religion, the Healing Church, developed. Said blood is also the cause of the Beast Curse; it's actually the blood of an Eldritch Abomination and transforms those exposed into beasts.
• In Clive Barker's Clive Barker's Jericho (by Clive Barker), the character of Wilhelmina "Billie" Church is a blood mage, whose spells can bind enemies and set them on fire. Her blood magic and abilities are also very important to certain aspects of the story.
• In the Dominions series, spells from most schools of magic are cast using "gems" which are basically elemental forces (fire, water, etc...) concentrated into portable form, and the casting prices of spells are listed in these gems. Instead of gems, however, one school of magic lists spell prices in blood. These prices are listed in increments of one blood slave, each of which must be drained completely empty, with high-level spell costs running into the hundreds. And true to the trope, blood magic is enormously powerful. Going deep into blood magic and relying completely on the armies of demons it allows you to summon is a valid strategy all by itself. Some of the strongest nations in the game are that way because of how well-suited they are to that strategy.
• Dragon Age:
  • Blood Magic, which uses Cast from Hit Points types of magic (and not necessarily the caster's hit points). A Tevinter Imperium blood mage even uses his own henchmen as sacrifices, usually by making them explode with the words "A blood sacrifice! For power!"
  • "Reavers", a particularly dangerous type of warrior that become stronger through suffering and exhibit certain magical powers, are created by drinking the blood of dragons. There are entire cults that spring up around high dragons for this reason. Some members of the Qunari race have been known to develop Reaver abilities purely through training. The implications of this have not yet been fully explored.
    • Grey Wardens themselves are created by drinking a special cocktail of darkspawn blood and lyrium, which makes them immune to the darkspawn taint for a few decades, anyway. It also gives them the ability to sense the darkspawn though the darkspawn can sense them as well. The Warden's Keep DLC also confirms that Grey Wardens can gain other abilities through their tainted blood.
• Messiah: Satan feeds on human blood, which is what he needs to "physically exist in the Earthly realm"; he also seemingly derives his power from it. Scientists' logs in the final level suggest that he managed to break free from his imprisonment in the research facility when they accidentally gave him too much blood to drink.
• The vampiric Revenant in Nexus Clash can drink the blood of other supernatural beings to get New Powers as the Plot Demands. There are many different outcomes from drinking blood, that each grant a different power based on whose blood you drank.
• In Ōkamiden, the Big Bad Akuro must bathe his vessel in blood to become perfect. Specifically, Orochi's blood. Or, maybe he has to bathe himself. The game can't agree with itself on this point.
• In Touhou Project, Remilia Scarlet has power over blood, and possibly so does her little sister Flandre. Apparently she can do many things with it. As Marisa so eloquently put it: "Blood is amazing!"
• In the teaser for Vampire: The Masquerade – Bloodlines 2, the narrator states: "Safety is bought with blood. Yours... theirs... ours."
• In Vanguard Bandits, the monstrous Zulwarn ATAC needs Blood in order to run.
• In World of Warcraft death knights have power over blood. Those that specialize in it can apparently suck blood they've lost back inside them through Death Strike (or possibly drain it from their enemies into themselves, how it's supposed to work isn't entirely clear), create a "blood shield", boil the blood of the enemies, and create bloodworms to attack their enemies. Which burst from gorging themselves, healing nearby allies through a mechanism that appears to be showering them in other people's blood. All in all it's pretty Squicky.
• This is part of the plot to Zelda II: The Adventure of Link. Link killed Ganon in the original game, but several of his minions are still running amok in Hyrule. While he goes on the eponymous adventure to return six crystals to six palaces, he has to be careful; the minions want to kill him so they can scatter his blood on Ganon's ashes and return him to life.

Web Comics

• In Hungry City, vampire Jerome becomes more powerful when he gets his fill of blood and weaker when he's thirsty, so the human main character has to feed him her own blood so that he'd have the strength to defend her from zombies.
• In Public Humiliation, Pooka blood is needed to power magic runes used for all sorts of things in modern society. Originally, it was freely given by Pooka to their allies, but when they were tired, and tried to say "no more", they found that their "allies" had become just another foe. Needless to say, when a Pooka hero did show up, things got messy.
• Subverted in Sluggy Freelance. Torg finds out that his talking sword Chaz only has its mystical abilities to speak and kill damn near anything if it has fed on the blood of the innocent first, and so assumes it's an evil sword. Chaz clarifies that it is simply a weapon, and whether it does good or bad things is entirely up to the person using it.
• In Tower of God, King Jahad transfers power to the Princesses of Jahad, his adopted daughters, by his blood.
• Seems to be a thing for The Fair Folk in The Weave; a Blind Seer fairy can tell who and what protagonist Tally is and what'll be her purpose by drinking a drop of her blood, and another who's dying binds her ghost to Tally by getting her blood into Tally's own wound.

Web Original

• In the Breeniverse series lonelygirl15 and KateModern, infusions of Trait Positive blood can extend the human lifespan considerably. In LG15: the resistance, Maggie's blood grants total immortality.
• Fey of the Whateley Universe used the blood of Hekate to throw a major Sidhe curse on her: a three-fold return of all the evil Hekate had done, which (given just what we've seen) will be horrific.
• Critical Role: The Homebrew Blood Hunter class, created by Matthew Mercer, absolutely runs on this trope. Most of the class' abilities (reffered to as "Hemocraft) are powered by spilling your own blood to do things like coat your weapon in elemental magic, or inflict nasty curses on your enemies.

Western Animation

• Avatar: The Last Airbender and its Sequel Series The Legend of Korra have bloodbending. A twisted version of waterbending that essentially allows the user to manipulate the blood flowing through living creatures' bodies: crushing internal organs, controlling living bodies like puppets, severing chi pathways.
• Within the world of The Owl House, the single strongest source of magic is Titan's Blood, which is so powerful that just a few drops of the stuff is enough to rip holes in the fabric of spacetime.^note For comparison's sake, four palismen working in tandem were able to power a Portal Door leading to the Void Between the Worlds that lasted for a fraction of a second before collapsing. A tiny bit of partially dried out Titan's Blood was able to achive the same effect and remain semi-stable for several hours. As a result of this, the fossilized caves that were once their veins are pretty much immune to all known forms of magic and every known deposit has been harvested long before the present day.
• Skull Island (2023): The origin episode reveals that the Big Bad, an extremely malevolent Kraken, was originally hibernating underwater until contact with a drop of Kong's blood awoke it. As observed by Goji Center in this vid, the implications that the Kraken likely slept through the tumultuous events of Kong: Skull Island undisturbed (which included seismic charges carpet-bombing the island) would have to mean that Kong's blood contains some special property as an Alpha Kaiju that was needed to make the Kraken wake up and become fully active again.

Type O

Anime & Manga

• In Death Note, Villain Protagonist Light Yagami kills people by writing their names in pages of a supernatural notebook. For emergencies, he keeps a needle and scrap of Death Note paper in a secret compartment in his watch, which means that even in tense situations where he's under surveillance, he can murder people by discreetly writing their names in his own blood.

Comic Books

• Spider-Man: Carnage has an alien symbiote mixed into his bloodstream that allows him to shape his blood and use it as a weapon. This is sometimes played for a more horrific effect, particularly in Warren Ellis and Kyle Hotz's Body Horror laden graphic novel "Mindbomb"
  Carnage: My blood wants to kill you!

Literature

• In Robert E. Howard's Conan the Barbarian story "Shadows In Zamboula" Baal-pteor offers Human Sacrifice with a Neck Snap, to save blood for the god.
• Harry Potter: Dolores Umbridge and her blood quill uses this, which clashes horribly with her otherwise Kawaiiko persona. It serves as one of the biggest clues to how much of a nasty piece of work she really is.

Tabletop Games

• The New World of Darkness sourcebook Immortals includes humans who prolong their lives by bathing in blood. Whereas the earlier Vampire: The Requiem game line leans on the Hemo Erotic element of vampirism, Immortals stresses how viscerally disgusting a blood bath would be and how every blood bather is, at best, a prolific Serial Killer who rationalizes their crimes.
• This is why Vampires in Shadowrun attack people and drink their blood — Shadowrun vampires actually drain Essence to survive, but Essence Drain only works when the victim and predator are connected on a deep, emotional level. It just so happens that for most vampires, the easiest emotion to connect with your victim is "fear", and drinking someone's blood while they're watching helps tremendously.
• Warhammer 40,000:
  • In Graham McNeill's Horus Heresy novel Fulgrim, the influence of the Laer temple causes Serena to add blood to her paint in hopes of capturing the vivid colors she imagines. She seduces Leopold in order to murder him for his blood.
  • For that matter, one could count anyone who worships Khorne, the GOD of Blood.

Video Games

• Bloodborne uses blood both in its mechanics (as seen in the AB section) and as a centerpiece of its particular brand of horror.
• In the climax of ICO, we see the only blood in the game when Ico's horns snap off. The sudden physical sign of violence after a game full of whacking nothing but intangible Smokemen is like a punch to the gut.

Web Comics

• In Hanna Is Not a Boy's Name, Hanna's blood is apparently particularly disgusting, at least according to a vampire. He attributes this to his use of magic (before quickly changing the subject).
  Hanna: It must be because I use magic, it taints my blood, but ANYWAYS.
• In Roza, her blood is magical. It glows.

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