History Main / BloodMagic

** In ''VideoGame/DevilMayCry5'', the Qliphoth tree's roots absorb human blood. When enough blood is absorbed, the tree then produces a fruit that grants massive power to any demon that eats it. Mundus became the ruler of the demons by eating a Qliphoth fruit in the past, according to Trish. Urizen's goal is to do the same. An in-game document file also states human blood as the source of demonic power.

* ''VideoGame/BrutalLegend'': An inadvertent version. When Eddie is badly injured due to the carelessness of the idiot band he works for, his blood drips onto his belt buckle and summons Ormagoden, kicking off the events of the game.

* ''Series/ShadowAndBone'': The offensive application of Heartrender abilities — they can control opponents' circulation to incapacitate them.

Some blood may be indicated to be more powerful than others. Common types are human blood, monster blood, the [[RoyalBlood blood of royalty]], the blood of a special line, the blood of an innocent, a child's blood, the caster's own blood,[[note]]as a self-sacrifice, this version is the only one even remotely likely to be practiced by good characters[[/note]] or [[VirginSacrifice virgin's blood]]. Sometimes only a single person's blood has power, and any other blood is powerless. Sometimes it also makes a difference whether the blood being used was offered willingly or taken unwillingly.

* ''Manga/MyHeroAcademia'' has villains with blood-related powers -- HeroKiller Stain can paralyze people whose blood he ingests for a certain amount of time (depending on their blood type), while his LoonyFan Toga can shapeshift into people whose blood she ingests. Notably, there's a teacher at UA who has a "Blood Manipulation" quirk, but he has not yet been seen in action.

[[folder:Light Novels]]
* In ''LightNovel/{{Overlord}}'', [[OurVampiresAreDifferent Shalltear Bloodfallen]] gathers the blood of her victims into an orb that hovers above her. She can use the blood as a substitute to mana, or she can [[BloodBath bathe herself in it]] to [[TheBerserker drastically increase her strength at the cost of becoming uncontrollable]].
* One of the spells granted to Naofumi in ''LightNovel/TheRisingOfTheShieldHero'' by the [[EvilWeapon Wrath Shield]] is called "Blood Sacrifice". The spell violently pulls out much of Naofumi's own blood to summon a giant maw of fangs to bite down on and crush his victims to death.
* ''LightNovel/TorturePrincessFremdTorturchen'': Demon magic is functionally what Creator/CharlesStross termed "algemancy": mana for spells is generated through inflicting pain on others.
** After being fed demon flesh by her EvilUncle Vlad, Elisabeth Le Fanu gained this ability, eventually [[WhereIWasBornAndRazed butchering the entire population of her hometown in an orgy of violence]] that transformed her into a being called the Torture Princess--ironically gaining the ability to generate her own mana ''without'' needing to torture people.
** In volume 3, Kaito Sena figures out that [[spoiler:the victim of torture doesn't actually need to be human to generate mana from it. He's able to generate sufficient mana to power his contracted demon for that volume by brutalizing another demon's contractor.]]
[[/folder]]

* ''Literature/OfFireAndStars'': Queen Invasya used a blood ritual to gain her magic, rather than having have a [[ReligionIsMagic bond with a god]]. This set a precedent-her people started doing it widely, and not worshiping the gods at all.

-->[[spoiler:'''Granny:''' I ain't been vampired, ''you'' been Weatherwaxed!]]

* ''Fanfic/HeartsOfIce'': Using blood of an acient dragon, Shampoo and Cologne cast a spell to banish Akane from the mortal plane.

* In the ''Fanfic/EmpathTheLuckiestSmurf'' story "Where The Wind Carries You", which is an adaptation of [[WesternAnimation/TheSmurfs the cartoon show]] episode "Never Smurf Off Till Tomorrow", Tapper (who [[{{Retcon}} appears in the place of the adult Nat Smurf]] among the Smurfs who were taken by the hurricane and dumped inside a volcano from which they escape) claims the blood of Jesus Christ over himself and his fellow Smurfs to protect them from the sharks that come swimming around them, ready to devour them. Whether it is because of this or what Tapper says, the sharks eventually swim away, leaving the Smurfs unharmed.

* In ''Manga/DeliciousInDungeon'' [[spoiler: this is revealed as Marcille's true specialty. She can draw from an "infinite" pool of power and perform very complex, potent ancient magic, but the spells require varying amounts of blood, are very taxing in terms of mana usage and might take a light toll on her sanity (however the latter is up to discussion since rapid mana drain tends to do this).]]

* In ''Fanfic/TheNightUnfurls'': Hugh's katana, the Chikage, has a rite that [[CastFromHitPoints feeds on the blood of its user]] and his enemies to enhance the damage dealt.

* Shinji in ''Fanfic/PointsOfFamiliarity'' bites off his finger and sacrifices it to ... ''something'' to create [Masks].
* ''Fanfic/ChildOfTheStorm'' includes both the ''Literature/HarryPotter'' and ''Literature/DresdenFiles'' variants, leaning hard towards the latter. It's not BlackMagic, but it is noted as being very dangerous, because it can be used for a number of purposes, mainly thaumaturgy (everything from tracking someone to biological manipulation via voodoo doll - though hair is noted as more reliable, because while blood's stronger, it doesn't last very long), particularly by vampires: drinking the right kind of blood supercharges a vampire (particularly Grey Court), while the right kind of ritual and device can imbue them with powers from it. Said ritual is why the Grey Court has ComboPlatterPowers.
** Plus, Dragon's blood and unicorn's blood both have extraordinary properties -- respectively, the 12 uses of dragon's blood, as discovered by Dumbledore and Nicholas Flamel, and granting life -- a cursed half-life -- no matter what.
* Subverted in-universe in ''Literature/TheDresdenFiles'' fanfic ''Fanfic/FairVote''. The protagonist uses tea as a metaphysically symbolic substitute -– and it works.

* ''Fanfic/EscapeFromTheHokagesHat'' has Naruto with multiple seals placed on him (by various Konoha ninja) to limit his growth. They were all made with blood. His own. After many a beating. Judging from a bit of dialogue between Tsunade and Shizune when they find out, placing a blood seal on someone is implied to be excruciatingly painful. Naruto got them between the ages of 6 and 9.
* In ''Fanfic/PerfectionIsOverrated'', Toki's Child, Cronos, has the ability to spawn black dragon minions from its own blood. She sends them back in time in order to alter [[Anime/MyHime Mai, Natsuki and Nao's]] pasts to prevent them from ever coming to Fuuka Academy, and after that plan is thwarted, sends them against the three when she faces them in combat.
* In ''Fanfic/ANewOrder'' main character Anime/SailorMoon can only use her [[WaveMotionGun strongest spell]] when she is injured and bleeding. The more blood she's lost, the stronger it is.
* In the Harry Potter/Disgaea {{crossover}} ''Something Wicked This Way Comes'', Voldemort's locket horcrux is sealed behind a wall requiring blood, like in canon. Etna wonders why he didn't think to key it into his own blood, instead of making it so that anyone could enter if they cut themselves.
* ''Fanfic/FalloutEquestria'': The first power that the [[TomeOfEldritchLore Black Book]] gives is a spell to turn blood into knives. This is by far the least horrible of its abilities, intended as a first taste to corrupt someone into taking more. Several characters use this power in the story, invariably to murder people painfully. Littlepip, however, realizes there's nothing preventing her from giving the blood a different shape, and [[BadPowersGoodPeople mostly uses it to create artificial clots for medical purposes]].
* Team 7 (Naruto, Sasuke, and Hinata) aka Team Lie (and later Neji) in ''Fanfic/PeopleLie'' make a pact with Kyuubi, "Blood for power, power for blood." They deliberately sacrifice blood in exchange for power; Naruto enters his canon SuperMode whereas Hinata, Sasuke, and Neji all gain more powerful forms of their doujutsu.
* ''Fanfic/ImGivingYouANightCall'': Alchemy can only be activated by applying blood to an array. The Elrics are unique in that they need very little blood to activate an array.
* In ''Fanfic/LokiAgentOfDoomgard'' a MadOracle's advice is to use Loki's own blood for tracking spells. As they're searching for alternate versions of themself this proves surprisingly effective.
* In the ''Webcomic/HetaliaAxisPowers'' fanfic ''[[https://www.fanfiction.net/s/9412929/1/ Hetalia School for Vampire Hunters]]'', most magical rituals involve this to some degree, usually using your own blood to form intricate symbols, which then casts the desired magical result.
* Root uses some in the ''Fanfic/CatalystVerse'' after Control tortures her, killing all of Control's guards instantly and allowing her to escape.
* The ''Franchise/AssassinsCreed'' fanfic ''[[https://archiveofourown.org/works/5856241 Hellfire]]'' involves lots of this, as Malik is a blood mage.
* ''Fanfic/{{crawlersout}}'': While Gellert Grindelwald studies magic in all its forms, there are certain magicks that not even he, a Dark Lord, is willing to practice -- BloodMagic is one of them. [[spoiler:It's a sign of desperation that he's willing to search for a master of this particular magic in order to find Fem!Harry. Even then, the guy refused to do anything for him as he felt that his expertise was unnecessary, suggesting that even he was wary of the magic he practiced]].

* In the ''Fanfic/EmpathTheLuckiestSmurf'' story "Where The Wind Carries You", which is an adaptation of [[WesternAnimation/TheSmurfs the cartoon show]] episode "Never Smurf Off Till Tomorrow", Tapper (who [[{{Retcon}} appears in the place of the adult Nat Smurf]] among the Smurfs who were taken by the hurricane and dumped inside a volcano from which they escape) claims the blood of Jesus Christ over himself and his fellow Smurfs to protect them from the sharks that come swimming around them, ready to devour them. Whether it is because of this or what Tapper says, the sharks eventually swim away, leaving the Smurfs unharmed.
* In ''Fanfic/TheConfectionaryChronicles'', the first true ritual Hermione performs for Loki is a blood sacrifice where she cuts her arm and chants worship to Loki over a stone altar she’s assembled. She later [[spoiler:guides Fleur in performing a more detailed ritual when Fleur asks to join her in giving thanks to Loki]], but most of the time Hermione just prays to Loki with offerings of sweets and chocolates, and only performs a ritual on special occasions.
* In ''Fanfic/EquestriaDivided'' [[NatureIsNotNice Fluttershy]] creates [[BiologicalMashup Everfree Wraiths]] by infecting ponies with her blood.
* ''Fanfic/DungeonKeeperAmi'': Blood contains mana, which can be used to power magical things, as said in "A Capture", when wondering how to power something:
--> Blood. [...] the mana within is easily assimilated.
* In ''Fanfic/AllThatGlittersOthellia'', Anna and Hans exchange blood to break an enchantment protecting a cave they need to enter.

* In ''Fanfic/TheAlarmaverse'' fic "Alarm Clock", a dark summoning ritual is accomplished by somepony [[spoiler:getting a bloody nose and walking to get medical supplies, dripping blood all over the long-forgotten ritual site]].
* In ''Fanfic/RabbitOfTheMoon'', becoming a Hunter gives Bell access to the Old Blood, allowing him to greatly increase his strength and skills through the Blood Echoes of the monsters he slays. He can also ingest or inject other sources of blood to heal himself, dye bullets with his own blood to injure the monsters of Yharnam, among other things.
* ''Fanfic/{{DNMC}}'': D'Arg is able to set his swords on fire by using his blood, which happens to be infused with [[AppliedPhlebotinum Dust.]] What qualifies it for this trope is that Dust ([[WebAnimation/{{RWBY}} apart from its canon counterpart, at least]]) is described as magic in "DNMC: Jeshile".

* ''Fanfic/TheRigelBlackChronicles'':
** Harry doesn't make a deep study of blood magic, but she has enough of the basics to know that it's important to carefully clean up any blood you've spilled, especially if it was done willingly, lest someone get hold of it and use it against you. [[spoiler: Her opponent in a Triwizard duel is less careful, and pays for it.]]
** Two of the Triwizard Tasks demand blood payment in order to pass barriers. [[spoiler: Turns out that Voldemort had an agent get hold of the samples so that he could use it in a ritual to steal Harry's magic. Fortunately, she was savvy enough to use someone else's blood instead of her own, making the ritual backfire.]]
* In the ''Series/GameOfThrones'' fanfic ''Fanfic/ThereAndBackAgain'', The Stranger explains to Jon Snow that everyone has magic in their blood; most normally have enough to keep them alive, but Jon, as the Prince who was Promised, is imbued with much more power, which was siphoned away from him by Bloodraven to Bran Stark and Daenerys Targaryen. Consequently, the ritual that Daenerys enacted to hatch her dragons does not require a HumanSacrifice; Jon needs only to cut his hand and spread the blood over the eggs as they sit over a fire to hatch the dragons. Contrast with Daenerys who had to sacrifice Mirri Maz Duur to hatch her dragons in canon.

* ''Wiki/SCPFoundation'', [[http://www.scp-wiki.net/scp-2791 SCP-2791 ("Fauste Bank plc").]] The SCP-2791 creatures use blood magic contracts as part of their procedures to set up their convoluted DealWithTheDevil schemes.

** ''VideoGame/WarcraftII'': Death Knights, after being researched at the [[NamesToRunAwayFromReallyFast Temple of the Damned]] gain the spell Unholy Armor, which adds a [[NighInvulnerable nearly impenetrable]] [[ExactlyWhatItSaysOnTheTin suit of armor]] [[CastFromHitPoints at the cost of half of the target's HP]].
** ''VideoGame/WarcraftIII'' introduces Blood Mages, but despite the name they ''don't'' practice any of this; most of their spells are fire-based. Lampshaded by one you meet in the Blasted Lands, who says Blood Mages "eat normal food like normal people."

Some blood may be indicated to be more powerful than others. Common types are human blood, monster blood, the [[RoyalBlood blood of royalty]], the blood of a special line, the blood of an innocent, a child's blood, the caster's own blood,[[note]]as a self-sacrifice, this version is the only one even remotely likely to be practiced by good characters[[/note]] or [[VirginSacrifice virgin's blood]]. Sometimes only a single person's blood has power, and any other blood is powerless.

* Some of ''Manga/{{Naruto}}'''s [[SummoningRitual Summoning Rituals]] use this.

* Some of the magic in ''Manga/NegimaMagisterNegiMagi'' works like this. At one point, Negi bites his thumb hard enough for blood to pour out, then creates magic circles for The Thousand Bolts (the ultimate lighting incantation) and pulverizes a mountain sized rock. Blood of powerful mages also seems to carry a certain amount of energy in it if Evangeline is to be believed. ''If.''

* ''[[Literature/AMagesPower A Mage's Power]]'': Members of the Bladi Clan have a unique branch of magic that uses their blood as its catalyst. The blood of anyone else is useless for magical purposes.

* In ''Manga/FullmetalAlchemist'', Ed and Al used their own blood as an ingredient in their attempt to resurrect their mother. When that failed miserably, costing Ed a leg and Al his entire body, Ed used his blood to draw a seal on a nearby suit of armor, binding his lost brother's wayward soul to it. This is justified by noting that the iron in the hemoglobin bonded with the iron of the armor, and the destruction of the bloodseal would kill Al.
** Later, when [[spoiler:Martel is killed while inside Al]], some of her blood runs down and over Al's blood seal, making him black out. However, this also allows him to remember what happened to him [[DeathAmnesia beyond the Gate]].
** The transmutation circle to generate a Philosopher's Stone [[spoiler:needs to have five "crests of blood" made from killing. For the nationwide transmutation circle, five gigantic military engagements which could be more aptly called butcherings created the five crests needed to cover all of Amestris.]]
** In the movie, The Sacred Star of Milos, the eponymous Sanguine Star is a Philosopher's Stone created by sacrificing the blood (not the souls) of several dozen soldiers.

*** In TheMovie based off of the 2003 anime, the circle to open the Gate only activates when it gets in touch with blood. Edward has a little blood on his glove the first time he opens it. The second time [[spoiler:Hohenheim gets mauled by Envy, while in Amestris Wrath dies.]]

** In the [[Anime/FullmetalAlchemist 2003 anime adaptation]], Mustang ends up creating a transmutation circle out of his own blood [[spoiler:in order to defeat Pride.]]

* In the world of * ''Literature/DraconisMemoria'', the Blood-blessed are empowered by drinking (raw or distilled) drake blood. They make up 0.1% of the global population, and can be identified by the reaction their skin has when coming into contact with drake blood – while regular tissue is burned by the substance, a Blood-blessed’s skin will instead turn a pale white. The power of a Blood-blessed depend on their proficiency with different types of blood – most will only excel in one type of power, with very rare exceptions who excel in all of them equally. Different kinds of drake blood will allow different powers to manifest:

* In ''Fanfic/AllThatGlitters'', Anna and Hans exchange blood to break an enchantment protecting a cave they need to enter.

** In ''VideoGame/DevilMayCry5'', the Qliphoth tree's roots absorb human blood. When enough blood is absorbed, the tree then produces a fruit that grants massive power to any demon that eats it. Mundus became the ruler of the demons by eating a Qliphoth fruit in the past, according to Trish. Urizen's goal is to do the same.