"For he to-day that sheds his blood with me shall be my brother."Where two people have made a pact with each other. The reasons for this tend to vary, but most often, it's because one or both of them owes the other his life — frequently in battle. From this moment on, they are brothers. Brothers in the sense that they will do anything to protect and, if necessary, avenge the other. Sometimes this is portrayed with the two taking a Blood Oath, cutting themselves to "mix" their blood. Thus, the trope name. (Don't Try This at Home; these rituals carry a risk of bloodborne infections like hepatitis and HIV in this day and age.) This trope is very common with Proud Warrior Race Guys, as well as a popular theme in kung fu movies. It's also quite popular in Heroic Bloodshed movies featuring The Triads and the Tongs, who have Blood Brotherhood as a central theme of their organization, best expressed through the 36 Oaths that formal triad members take, which basically boil down to "Do not screw over your sworn brothers, or you will get chopped up by lots of blades." Being criminals, however, Triads and Tongs can be just as prone to backstabbing and betrayal as any other criminal organization, which is especially shown in the grittier cinematic portrayals. Often, Blood Brothers spend so much time with each other that they're Heterosexual Life-Partners. See also True Companions, for when a group of people, because of circumstance, are as close as real family would be. For the musical, see Blood Brothers. Compare Fire-Forged Friends, Bash Brothers. A Sub-Trope to True Companions. Note that all examples must include an oath, pact, or other explicit bonding; if it doesn't, it's not this trope.
— Henry V
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Anime and Manga
- In the Fushigi Yuugi series, Genbu Celestial Warriors, Hikitsu and Tomite are the classic pair.
- The whole Koihime†Musou is about this, being based off of the Romance of the Three Kingdoms.
- Simon and Kamina from Tengen Toppa Gurren Lagann aren't related, but Kamina declares them to be "soul brothers" and insists that Simon refer to him as a brother.
- The manga Gorgeous Carat has Ray and Azura who became blood brothers as kids, complete with mixing of blood. Things go downhill in the present when Azura is revealed to be evil, and is the villain for most of the series.
- In One Piece, Luffy, Ace and Sabo were not related by blood, but they were very close, and one day made a ceremony of drinking sake all at once, at which point they became brothers. Sabo admits in his farewell letter that the brotherly bond between the three of them is his greatest treasure, and the Dressrosa Arc makes it clear that the years of separation hasn't changed that. What is briefly shown of Sabo's reaction to Ace's death cannot express the sheer pain it caused him as he cries out in grief. Sabo makes it clear to his enemies that he would do anything and everything for Luffy, his precious little brother. In turn, nothing can express the sheer joy on Luffy's face when he learns that he still has one brother left in the world, and can only resort to Inelegant Blubbering.
- In Nurarihyon no Mago, the youkai make pacts amongst each other to be sworn brothers.
- The cast of K-On! are one of the rare female versions of this trope.
- Similarly, the Four-Girl Ensemble of A Certain Scientific Railgun also count.
- Diva's Chevaliers in Blood+ refer to each other as blood brothers since they have all been turned into Chevaliers because of Diva's blood.
- Reinhard and Kircheis in Legend of Galactic Heroes are this along with Hetero Sexual Lifepartners. Their friendship started out when Reinhards sister (whom Kircheis is in love with) asks Kircheis to be his friend. Then, Reinhard asks for Kircheis help in conquering the galaxy. And so the two rise up in ranks, Reinhard as the shining star and Kircheis supporting him from behind. And then Kircheis dies (very early on, to boot), something that has lasting effects on virtually everyone for the entire rest of the series.
- In Saint Beast, Judas repeatedly asks Luca to stand by him, and when he tries to do things alone Luca reminds him that alone means both of them.
- G.I. Joe: Joe has Snake Eyes and Storm Shadow, who are the equivalent of Blood Brothers ("sword-brothers") and have indeed saved each other's life in battle. Sometimes even while actively trying to defeat/kill each other. Heavy on elements of The Only One Allowed to Defeat You, Enemy Mine, and Brainwashed and Crazy, the latter on Storm Shadow's part (at least when they're on opposite sides). Storm Shadow saving Snake Eyes' life is an integral part of their backstory.
- There's a pair of Marvel Comics villains known as the Blood Brothers, who are formidable separately but increasingly unstoppable the closer they are to one another..
- In a Spider-Man/Wolverine crossover by Jason Aaron, the two heroes end up bouncing back and forth through time due to the machinations of X-Men villain Mojo. Toward the end of the series, when they seem to have settled in the Wild West, Logan (who had taken up with local tribe) performed a blood-brother ritual with Peter Parker. Regrettably this seems to have been forgotten after the mini-series ended.
- Creator/IDW's version of The (G1) Transformers have a similar concept called Amica Endurae.
- The French comic Les Aigles de Rome, has the two protagonists (Ermanamer and Marcus, the first is a Germanic youth raised as a hostage in Rome, the second is a Roman born of a Germanic concubine) become blood brothers after they kill a bear.
- Mortality has this with Holmes and Watson. Heck, Watson outright says "if your master's actions destroy him whom I regard as-as the best and wisest man I have ever known, make no mistake that I shall hunt down, to a man, everyone who played a part in his destruction."
- Happens sometimes in Knights of the Old Republic fanfics (more for the first than the second) with Canderous and the Player Character...but sometimes all the crew gets marked as vode. The Mandalorian language doesn't make the distinction between "friend" and "family member" after all.
- Naruto and Haku become Sworn Brothers in the fanfic A Father's Wrath, swearing an oath in a Peach Garden.
- Littlefoot and Skytail's packs become allies after a ritual involving a vow and the shedding blood in The Seven Hunters, a The Land Before Time fanfic.
- Warband Of The Forsaken Sons uses this trope in order to avoid the usual betrayal in Chaos Space Marines groups. Since all members have fought together against legions of daemons for months without a moment of respite, they are bound by more than their loyalties to their respective Legions.
- In Spirit Of Redemption turians have an actual ceremony for swearing blood-brotherhood (or sisterhood), wherein they vow to take care of each other's families and responsibilities should one of them die.
- In Son Of The Seven Kingdoms William Baratheon, Robb Stark, Jon Snow and Theon Greyjoy are like this. William even telling them when he has to leave The North that he considers them more than friends and are his Brothers regardless of blood and name. Because of the bonds of friendship between them, this causes Theon to instead of rejoining The Ironborn, to swear his loyalty to him.
- Even at infancy, Harry in Scion of Sorcery is considered Neville this due to their ties to prophecy and the fact that Sirius took Neville in after his parent's death and is also Harry's god-father.
- The sake tradition between Luffy, Ace, and Sabo is repeated in This Bites! by Cross, Zoro, and Nami after the Thriller Bark saga, though the tradition is slightly spoiled since instead of sake, they accidentally used a fiercely overpowering vodka.
- The film version of Othello has Othello forcing Iago to perform a blood pact.
- A Better Tomorrow: Mark Gor (Chow Yun-Fat) and Sung Tse Ho (Ti Lung) from John Woo's film are probably the best known examples of Blood Brothers in a Heroic Bloodshed movie. In fact, most of John Woo's Heroic Bloodshed movies tend to have two characters develop such a bond with each other during the course of the movie.
- The Warlords (starring Jet Li, Andy Lau, and Takeshi Kaneshiro/Jin Chengwu) has the three actors' characters playing sworn brothers along the lines of the Peach Tree Oath quoted above, but with tragic consequences since it doesn't hold nearly as well.
- In the 2009 Sherlock Holmes film, a fortune teller reads Watson's palm and refers to "two brothers, not of blood but of bond". While this trope is probably true of them anyway, her actual statement is suspect because Holmes put her up to saying it.
- An old Bud Spencer spaghetti-Western, where the (anti)hero, played by Bud Spencer, had a rather dim Native American sidekick, who followed him around due to them being 'Blood brothers', since Bud had once saved his life with a blood transfusion.
- Star Wars: Han Solo and Chewbacca are Blood Brothers. While Han Solo most likely didn't think so when he first rescued Chewie, Chewbacca felt he had a "life debt" to Han. At first the "brotherhood" was mostly one way but as they traveled together and Han learned more about Chewie and the "life debt", they became true Blood Brothers.
- According to the liner notes on The Blues Brothers album, Jake and Elwood Blues, unrelated orphans growing up in the same dismal orphanage, swore an oath of Blood Brotherhood by cutting their fingers with an E-string allegedly from Elmore James's guitar, essentially adopting each other. The Mission from God came later. According to the book Blues Brothers: Private, they also had their names legally changed in 1962, taking the same last name and taking each other's first names as their middle names. The Mission from God came later.
- In Mongol, two ten year olds (one of whom is the future Genghis Khan) become blood brothers after one saves the other's life.
- Interesting twist in Practical Magic, where a pair of sisters swear bloodbrotherhood. This becomes a plot point a couple of times.
- In Son of Rambow, Lee Carter decides he and Will Proudfoot should become blood brothers after he saves Will from drowning.
- In the Taiwanese gangster film Monga the main character becomes blood brothers with his four best friends in a ceremony that echoes the Peach Tree Oath.
- The Outlaw Josey Wales takes a Blood Oath with Comanche chief Ten Bears to seal the peace between Ten Bear's Comanche tribe and Josey's "tribe" of white, Native American, and Hispanic settlers, implicitly making them blood brothers as well.
- In Wild Zero, Guitar Wolf cuts Ace's hand and his own to make them "rock 'n' roll blood brothers," and gives Ace a whistle to use if in distress.
- In McLintock!, Puma reminds McLintock of their blood-brother bond when they meet at the railroad depot.
- In Puss in Boots, Puss and Humpty Dumpty become blood-and-yolk brothers, pricking their fingers with a pin, then shaking hands.
- In Dirty Work, Mitch and Sam used rusty soda can tops in second grade to become blood brothers. Looking back on this moment now knowing they are actually half-brothers, Mitch jokes that it was a lot of trouble for nothing.
- In Excalibur, Uther and Cornwall become this when Cornwall yields to Uther after Uther receives Excalibur, signifying the right to be king. Uther then royally screws it up when he falls in lust for Ygraine, Cornwall's wife.
- Parodied in Return To Neverland, where Peter Pan and the Lost Boys spit in their hands and offer them to Jane during her initiation into their group.
- Nightfall Series: A darker example: vampires can become blood brothers after drinking each other's blood.
- Commonly seen in Wuxia literature.
- In Robert A. Heinlein's Stranger in a Strange Land, the Martians have what is called a "water brother." If you "share water" with someone, from that moment on, you are their brother.
- While water doesn't seem all that binding on a planet that is two thirds water, for the Martians it is a very valuable and limited resource and to share it with someone is a precious act of camaraderie.
- In Diana Wynne Jones's The Spellcoats, Kars Adon and Hern make a pact of undying friendship after Hern helps free Kars Adon's people from Kankredin. After Kars Adon takes a knife meant for Hern, he points out that they're now quite literally blood brothers.
- The Indian in the Cupboard: Little Bear and Boone, and Little Bear and Omri. The former pair became Blood Brothers by having their wrists cut and then bound together. The latter involved more of a prick on Omri's finger.
- In Darkness Visible Marsh and Lewis definitely qualify as this. Once they stop hating each other, that is...
- Mercedes Lackey's Heralds of Valdemar series:
- Tarma and Kethry of the Vows and Honor trilogy are Blood Sisters, complete with a blood-mixing ritual of clasped hands. The pair were given a stamp of divine approval from Tarma's goddess when the wounded hands were instantly healed upon contact, leaving distinctive scars.
- Talia eventually does this with both Skif and Kris. Would've been nice if someone had told Dirk that before he went all I Want My Beloved to Be Happy, but then I suppose we wouldn't have the third book.
- Mercedes Lackey also uses it in the Tales of the Five Hundred Kingdoms series; in order to stop the Tradition from making her fall in love with her rescuer, Princess Andromeda suggests the idea of becoming blood siblings with George instead. This might have been unnecessary, since George is a woman and it's unlikely the Tradition would make two women fall in love since that doesn't typically happen in fairy tales.
- Moby-Dick: Ishmael and Queequeg.
- Last of the Mohicans: Natty "Hawkeye" Bumppo and Chingachgook.
- In Romance of the Three Kingdoms, Liu Bei, Guan Yu, and Zhang Fei swear an oath of brotherhood under the tree of a peach garden as quoted above that lasts for their whole lives. They are not the only sworn brothers in the story (for example, Sun Ce and Zhou Yu) but by far the most famous, and for multiple chapters the extent to which Guan Yu will go to uphold this is a plot point, used both by and against him: in particular, Zhang Liao got Guan Yu to surrender to Cao Cao by saying that he shouldn't go out fighting while the missing Liu Bei might still need him), but Guan Yu conditioned that surrender as lasting only until he found his brother's whereabouts... and then openly rubbed the impermanence of this service in Cao Cao's face. Cao Cao however then made Guan Yu the General Who Doesn't Do Anything, up until his opposing warlord's main warrior was too much for Cao Cao's officers to handle and he was forced to pull Guan Yu off from the bench into his lineup.
- An Aiel ritual in The Wheel of Time can make you brother and sister, the ritual is shown in detail when Elayne and Aviendha go through it to become First-sisters.
- As a more literal example, several Borderlander monarchs go well out of their way to meet in person for a ritual of this sort, treated as much more serious than a written treaty.
- In The Bible, David and Jonathan, make a covenant (pact) and their souls are bound together, making this trope Older Than Feudalism. Jonathan will do anything to protect David, namely betraying his own family.
- Judge Dee's three lieutenants, Ma Joong, Chiao Tai and Tao Gan, consider themselves and refer to each other as Blood Brothers.
- In Conn Iggulden's Emperor series, Caesar and Brutus are blood brothers. 'Course, we all know how that turns out in the end...
- In his later Emperor series, Jochi and Jebe do the blood mixing thing.
- The Devil In Vienna has a female example, with Jewish Inge and Catholic Lieselotte copying a blood brotherhood ritual-drinking wine mixed with their own blood- from a western novel. They always sign their letter "B.S.L" for "Blood Sisterly Love."
- Hagan and Waldhari in Stephan Grundy's Attila's Treasure, especially poignant because of the huge differences between them. As the book progresses it seems as though their devotion to each other only grows stronger the wider the gulf between them.
- Horus Heresy: Saul Tarvitz and Nathaniel Garro. Instead of mixing blood, they carved an Imperial eagle into their gauntlets. It even states that there is only one member of the Emperor's Children Garro considers his brother - Tarvitz.
- In Rosemary Sutcliff's novel Blood Feud, English lad Jestyn is sold as a thrall to a Dane called Thormod, but after a few battles they realise they are inseparable. They become blood brothers after a blood-mixing pact.
- Novels of the Change: The anamchara ritual has this effect. Unlike most takes on this trope, it does not preclude romance.
- In the Xanth novel Centaur Aisle, two allies are wounded during an unbalanced swordfight, and one says, "Now our blood has mingled; we are blood brothers."
- In The Saga of Darren Shan, this is how vampires are made - a vampire gives a human some of their blood through fingertip cuts. This is why the war between the two groups of vampires (both Proud Warrior Races, by the way) becomes know as the War of the Scars.
- The entire point of The Sisterhood of the Traveling Pants. The girls practically consider themselves family being born around the same time and basically spending their entire lives together. It's in the title, man!
- Sherlock Holmes: Holmes and Watson are definitely this, and it's established in "The Three Garridebs" when Evans makes the stupid mistake of shooting Watson in front of Holmes.
- In Gisle Surssøns saga, one of the Icelandic lineage sagas, the protagonist Gisle makes a pact with his brother Torkel and his brothers-in-law Vestein and Torgrim. The four of them mix blood by each letting theirs flow into a hole dug into the ground whereupon they cover it with a tussock. In this way, they become sworn brothers who must avenge each other if either of them should be killed. It does not end well when Vestein is murdered and Gisle mistakenly believes that it was by Torgrim.
- Winnetou and Old Shatterhand in the books of Karl May. The ritual is seen in the movie adaptation Apache Gold after they initially fought. Old Shatterhand won in a match to death, showing that Manitu is on his side, and he was able to prove that he saved Winnetou's life previously.
- The title character of the Flashman novels swears blood-brotherhood with several characters, noting in Flashman at the Charge that he felt more solemnity in the act than any Christian oath.
- In Alvin Fernald; Superweasel, one of the Alvin Fernald novels by Clifford B. Hicks, pre-teen hero Alvin Fernald, his little sister Daphne and his best friend Shoie create an anti-pollution superheroic identity named "Superweasel". At one point Alvin hits on the idea of a blood oath to seal their heroic pact, but not wanting to hurt his little sister, has them smear drops of iodine on their hands instead of cutting them.
- Tarl Cabot becomes a blood brother to various characters a number of times over the course of the Gor series. In particular, Blood Brothers of Gor starts out by playing with the trope with Cabot having been Made a Slave by Canka for having saved the life of Canka's brother Cuwignaka but ends up being Exactly What It Says on the Tin.
- Li Cunxin and his friend The Bandit became blood brothers in the autobiography Mao's Last Dancer.
- Max and Ephraim in The Troop. Friends since they were babies; they decide to do this to cement their status as "Forever Friends."
- Robert Baratheon and Eddard Stark of A Song of Ice and Fire would certainly qualify, as would Theon Greyjoy and Robb Stark.
- In Updraft, despite the poor start to their relationship, Sellis declares herself and Kirit to be this after they both pass their challenges. It lasts less than an hour, which shouldn't really surprise either of them; no matter how exhilarating Sellis may have found her triumph, the fundamental differences between them are unchanged.
- Cassandra Clare is fond of this trope and uses it throughout "The Mortal Instruments" (Jace and Alec) and "The Infernal Devices" (Will and Jem). While both pairs certainly qualify, given the whole mystical-ritual-lifelong-oath thing, Will's and Jem's relationship is much more convincing than Jace's and Alec's; the former pair takes the 'I will kill or die for you' ethos to the Nth degree and their relationship is one of the driving motivators of the trilogy, while the latter pair's relationship exists but is rarely dealt with directly.
- Threadsiblings in The Witchlands are a regularly-occuring version of this, as they're pairs of people bonded with a strong Thread (magical connection) by a very powerful event, such as one saving the others' life. Threadbrothers and Threadsisters are very tightly bound - Merik feels closer to his Threadbrother Kullen than he does to his actual sister.
- In Star Trek, Kirk, Spock, and McCoy are Blood Brothers. This goes even further in the movie, Star Trek III: The Search for Spock, when we discover that Spock managed to put his "katra" (soul) into McCoy's mind just before he died.
- Played with in Buffy the Vampire Slayer, season 5. Although Dawn is confused about her own existence as Buffy's sister, an important scene involves Buffy and Dawn clasping bloody hands and Buffy declaring that the same blood, "Summers blood", runs through their veins. So not necessarily making them "blood sisters", but affirming the link that already exists.
- The Easy Company in Band of Brothers evolves into True Companions by stacking blood brotherhoods one after another.
- Sherlock: This is definitely true of Sherlock and John, and A LOT of episodes have emphasized on the Holmesian friendship dynamic.
- Particularly in the pilot where John kills Jefferson Hope to bust Sherlock out of a suicidal position.
- In Hercules: The Legendary Journeys, Hercules and Iolaus have admitted to loving each other as brothers. (The fanfic writers often choose to ignore those last two words.)
- Kamen Rider Kabuto uses this trope most clearly in the form of the Hopper Brothers: Yaguruma Sou (Kick Hopper) and Kagayama Shun (Punch Hopper).
- Pawn Stars: Chumlee and Corey are very much like brothers. Much to Rick's dismay.
- Ted declares this for Barney and Marshall in the season three finale of How I Met Your Mother, which causes Barney to start needling him about who's his best brother, in reference to his and Marshall's long running argument over who's Ted's best friend.
- Coupling has Jeff and Steve who grew up in school together, and have remained best friends even into their busy and commercial London lifestyle orientated adulthood. So close in fact, that they are in fact porn buddies. By Jeff's wording, when one dies, the other is morally obliged to go to their deceased friend's house and remove all of the porn before their family and colleagues find it. He even boldly defends this pact when talking to Steve's future partner to big his friend up. Disclaiming "that's how close we are!"
- On The Andy Griffith Show Opie & a new boy named Trey become blood brothers, only they use barn paint instead because they don't want to get an infection.
- Game of Thrones:
"Theon is my murdered father’s ward, I am my murdered father’s son. Like my father and Robert, bound in blood, if not by blood. We are brothers."
- Robert Baratheon admits that he has never truly liked his brothers, Stannis and Renly, and that he considers Ned Stark his true brother; the brother he "chose".
- Robb Stark and Theon Greyjoy were similarly bonded. In one of the DVD Extras, Robb Stark's voiceover directly addresses this.
- A Dothraki khal and his bloodriders share everything until the day they die.
- Stella does it with her foster sister in CSI: NY, in a flashback during the Cold Case crossover ep. The other woman kept some of the blood in a necklace vial, and when she killed someone in the other show's territory, the necklace broke and led the CC guys to New York.
- Mac and Dennis on It's Always Sunny in Philadelphia refer to themselves as "blood brothers".
- In Princess Returning Pearl, the two main characters Xiao Yan Zi and Zi Wei swear a pact to be sisters, to "enjoy happiness and suffer calamities together", though their oath was sealed with wine rather than blood.
- Punky Brewster: Punky, Cherie and Margaux felt disgusted at the notion of using blood so they instead became "ketchup sisters".
- Stargate SG-1: Near the end of the series, Teal'c tells O'Neill that he considers him like a brother.
O'Neill: Aren't you, like, 50 years older than me?
Teal'c: A younger brother, perhaps, but that is not the point.
- In the song "Goodbye Earl" by the Dixie Chicks, Mary Ann and Wanda are Blood Sisters. When Wanda is put into the hospital by Earl, they get together and kill him.
- Bruce Springsteen has a song named Blood Brothers which fits this trope perfectly.
- Iron Maiden has a song called "Blood Brothers" on this very topic. Interestingly enough, their song "The Clansman" about the strong bond between Scottish clan-member evokes this trope even more.
- Manowar, fitting with their general theme, also has a song called "Blood Brothers," which is about Blood Brotherhood and True Companionship in general.
- Papa Roach also had a song called "Blood Brothers", about people still sticking together in a violence-obsessed world.
- Norse Mythology:
- Odin, Chieftain of the Aesir, and Loki, trickster demigod, were celebrated blood-brothers, and Odin would never sit at a table where Loki wasn't welcome. This causes problems when, in the leadup to Ragnarok, Loki's villainy reaches new heights and Odin can no longer remain blind to it.
- Örvar-Oddr and Hjalmar, two heroes from the legendary sagas who became blood brothers in a ceremony after pouring their blood under some raised soil.
- In The Bible, David and Jonathan.
- The famous Anoa'i family, which pioneered the Wild Samoan archetype, was formed by Amituanai Anoa'i and "High Chief" Peter Maivia, two men who did see one another as blood brothers (Anoa'i's children referred to Maivia as their uncle). The family includes Afa and Sika Anoa'i (the original Wild Samoans) The Rock (Dwayne Johnson), the late Rodney Anoa'i (a.k.a. Yokozuna), Solofa Fatu (Rikishi), The Tonga Kid, and Eddie Fatu (known as
- In one of the 90s episodes of Titanes en el Ring, La Momia cut a ribbon, symbolizing the end of his feud with the late Martin Karadagian, and effectively making them Blood Brothers.
- All Space Marines ever in Warhammer 40,000. They even call each other "Brother", constantly, though this may be as much their
Catholic Space Nazismsomewhat monastic style as their fanatical loyalty to the Chapter and one another. The Blood Angels co-opt the quote from Henry V :"He who sheds blood with me today shall be my battle brother eternal."
- And they have all been sort-of genetically manipulated to be similar to their chapter's Founder, essentially making them his children.
- For a slightly more heretical version, teams of Tau Fire Warriors go through the Ta'lissera bonding ritual, producing their own squad-scale True Companions. It also gives them sufficient steel in their little blue backs to return even when eight of the original ten are dead, to avenge their fallen blood kin and kick ass for the Greater Good.
- Dungeons & Dragons
- In module CM1 "Test of the Warlords", the PC's can participate in the ritual of blood sharing with a barbarian chief. They do so by cutting their palms and clasping hands, thus mixing their blood.
- Ravenloft supplement Van Richten's Guide to the Vistani. A giorgio (non-Vistani) who performs a great service for the Vistani may be offered the honor of performing the blood rite. A Vistani cuts the left hand of the giorgio and himself and clasps hands with him. After tying a scarf around their hands, he speaks an oath that says they are brothers. When they separate their hands the wounds are healed, leaving a purple scar on the giorgio's hand that identifies him as a giogoto ("enlightened, yet not of the blood") to all Vistani.
- Basic D&D Module DA3 City of the Gods gives a chance of sand folk doing this ritual with your party as a means of friendship or adoption. However, their blood is slightly poisonous to the human characters (but only cause minor damage).
- 1st Edition supplement The Rogues Gallery. The lizard man Phoebus can make another character his "blood kin" by performing a ritual that involves a sharing of blood. If Phoebus or any of his blood kin die, the others will will know that one of them has died and can locate the body of the victim.
- Changeling: The Dreaming has the Oath of Clasped Hands, which is your standard blood-mixing ritual with in-game results. (Specifically, both parties get an additional point of Willpower for as long as the oath is upheld.) It's described as the platonic version of the Oath of Truehearts, which is expressly for lovers.
- This is also how motleys usually form up in Changeling: The Lost. Groups of changelings swear an oath on the Wyrd to come together for a common purpose, and usually gain mechanical benefits related to that area on the condition that they stand up for one another and don't flag in their pursuit. Likewise, there are other Oaths that provide similar benefits, such as the Ancient Pact (which is when a changeling swears one of these with a mortal) and the Vernal Oath (which is a marriage oath).
- In 7th Sea, the Eisen have the concept of the rucken — which means "back-brother" and is considered the the strongest oath an Eisen can give outside of marriage. The rucken is someone you can absolutely trust to have your back and vice-versa. Woe to anyone who betrays their rucken's trust and willingly breaks that vow.
- Ars Magica supplement The Order of Hermes. When two mages want to form a bond of amicus (intense friendship), they cut their wrists and place their wrists together to share their blood. Grogs sometimes do this too, and specifically call each other "blood brother".
- The musical "Blood Brothers", obviously. It goes very, very badly.
- Siegfried and Gunther swear blood brotherhood in Wagner's Götterdämmerung, with Gunther's half-brother Hagen presiding. Given that Hagen is evil, it's not surprising that this ends badly.
- Thrill Me calls upon this trope in, "A Written Contract". The contract stipulates that Nathan will help Richard with all his crimes as long as Richard has sex with him afterward. They sign in blood and then clasp their bloody hands, a gesture which is echoed in "Superior" to remind Nathan that they're in this together.
- Fatal Fury: Bosses Grant and Kain R. Heinlein have 'sworn an oath of eternal allegiance' to each other, as can be seen when they fight in versus mode.
- The "From this moment, you and I are Sworn Brothers" bit between Darunia and Link in The Legend of Zelda: Ocarina of Time.
- Darunia is also a Sworn Brother with the King of Hyrule himself.
- Also, Snake's codec call on the Ice Climbers in Super Smash Bros. Brawl implies that the Ice Climbers have formed this kind of bond with each other, though they're more like Blood Brother and Sister.
- Eventually, in Planescape: Torment Dak'kon does the Pronouncement of Two Deaths as One with you, effectively making you Blood Brothers until death.
- In another Black/Obsidian title, Knights of the Old Republic II: a dark side player character can become this with the beserker wookiee Hanharr. Notable as this may be the only positive relationship either of them have
- The walking tank aliens known as Mgalekgolo/Hunters in the Halo series always come in pairs, and whenever one is killed, the other goes in a berserk rage as it tries to avenge its partner's death. Specifically, Hunters are actually hive-mind colonies of Lekgolo worms encased in suits of armor, with a bonded pair of Hunters forming whenever a colony gets too big for just one suit; this means that a Hunter in "berserk avenger rage" mode is basically going "That guy just killed a entire city filled with our relatives. He needs to die."
- Solid Snake and Otacon in the Metal Gear series.
- Eliwood and Hector from Fire Emblem: The Blazing Blade, right down to the literal blood pact they made as children.
- Winfield, Thoma and Alberti in Agarest Senki definitely counts as this. They even have a Combination Attack with each other.
- There's a level in Modern Warfare 3 called "Blood Brothers". The title at first glance references the trope-fitting relationship between Soap and Price, and how the latter won't take the former's death very well. The level's name also references the flashback sequence at the end, which reveals the Blood Brotherhood between Makarov and Yuri, that Yuri walked out on.
- In Warcraft, Thrall, Cairne, and Vol'Jin consider each others brothers thru a 'Blood Oath' made sometime between the start of the Orc campaign in Warcraft III and the start of World of Warcraft. In fact, it's not too much of a stretch to say that the entire Horde and their counterpart, the Alliance, is basically this.
- Guild Wars 2 has Human guardian Logan Thackeray and Charr warrior Rytlock Brimstone started off trying to kill each other- a series of circumstances eventually led to the two becoming the best of friends within Destiny's Edge- making Logan's decision to leave the guild at a critical moment which cost the lives of another member and a powerful ally hurt all the more, leaving Rytlock bitter. The game spends time highlighting their division and patching things up. It's clear through it all that either of them will risk or give their lives to save the other- which is incredible given that Humans and Charr have until recently been at war with each other for more than 2 centuries, and even with recent alliances between the two races things are still rather lukewarm.
- Middle-earth: Shadow of War adds a Blood Brother system to Orcs and Ologs as part of its expansion to the Nemesis System. If one is killed, the other will likely attack you a few seconds later, and if the Blood Brother in question is part of your army, he will defect.
- In Homestuck, Karkat Vantas and his universe's version of Jack Noir team up to overthrow the Black Queen, sealing their pact with a bloody handshake. The "blood" part is especially important here, as Karkat sympathized with Jack Noir when he discovered that there was somebody else who had his mutant, "candy-colored" bright red blood.
- Karkat is also a Knight of Blood. The Blood aspect is mostly based on this trope, as it refers to the bonds of loyalty and friendship.
- In Girl Genius, Zeetha thanks Agatha for helping her by announcing that they are going to start Agatha's warrior training. This is a much more serious matter than Agatha initially thinks, and means that there's now an unbreakable bond between the two of them.
Zeetha: Know, Agatha Clay, that the warrior tradition of the royal house of Skifander is old, proud and jealously guarded. In this life I am allowed to train one other besides my own daughters. I have chosen you. The bond between us will be stronger than that of friends, of family, of lovers. As of now, we are "kolee-dok-zumil."
Agatha: What does that mean?
Zeetha: Ah - kind of hard to translate. Sort of like "teacher and student." Sort of like "cause and effect." Mostly, like "grindstone and knife." [hits Agatha across the head with her staff]
- The Saga of Tuck: The Euro-mutt title character and his Chinese-American friend, Mike, call each other brother when not trading blows. This isn't just rhetoric: the ritual is re-enacted more than once during the story and allows a kind of psychic link. Tuck claims he can't die unless Mike lets him go, and vice versa. This is so far unproven, but it was close.
- Carmilla and Fey, in the Whateley Universe, even going so far as making a blood pact.
- In The Gungan Council, Ryori and Ti'Cira went so far as to use blood in their pact to be faithful allies to each other. Darth Apparatus and Chaos Maxtor have a just as binding pact, minus the blood, where Chaos becomes the Darth's soldier while the latter gets functional immortality.
- Parodied in The Simpsons when Bart and Milhouse became "spit brothers", complete with spitting in the hands and clasping them. Ewww...
- Used in American Dad!, when Stan and his new friend become brothers. The next scene shows them both at a hospital for a blood test, happily showing each other the negative test results.
- Parodied on The Amazing World of Gumball when Tobias tries to cut his hand open with a blunt stick. It doesn't work very well and he keeps trying to tear the skin well into the next scene.
- In South Park, Stan and Kyle can be trusted to consistently treat one another like family, going to considerable lengths for one another in a variety of episodes (for example "Cherokee Hair Tampons", "Super Best Friends", "Imaginationland", "Guitar Queer-o", "Follow That Egg", "The List", "You Have 0 Friends"—you get the idea); Kyle even goes so far as to call Stan his brother in "Ike's Wee-Wee." However, they treat Butters and Kenny more ambivalently, and make no secret of their contempt for Cartman, making the dynamic between the South Park boys more indicative of two Blood Brothers surrounded by many morons.
- On Young Justice, Beast Boy and Miss Martian refer to each other this way after she gave him a blood transfusion.
- Brian and Stewie did this in Family Guy. Unfortunately, Brian gave Stewie herpes as a result, and it turns out he previously did the same thing with Chris.
- All Hail King Julien has a whole ceremony for having two men legally declared brothers called a Brother Marriage, or Brarriage. As the name implies, it is simply a re-skinned marriage ceremony, with no need for messy blood pacts.
- Temujin, who became Genghis Khan, formed a blood brotherhood with his best friend, Jamuqa, which was common in Mongolia at the time. To seal this, they cut themselves, dripped blood into fermented mare's milk, and drank each other's blood. Keep in mind, they were about 10 or 11 years old when they did this. Because Mongols are badass. Incidentally, Jamuqa ended up as Temujin's main enemy in the wars to unify Mongolia. But when Temujin finally captured him, he offered him a full pardon, but Jamuqa refused, suggesting that Temujin kill him. Temujin took his blood-brother's advice, and killed him, then gave him a proper burial. Because he was nice like that.
- To be more specific, they became enemies because Jamuqa had made his own bid to unite the Mongols. While the two had always supported one another, neither could accept the other's rule; Jamuqa compared it to there being only room in the sky for one sun, and only room in the world for one Mongol lord. Jamuqa also requested he be executed without spilling his blood; Mongol religious beliefs held that dying with your blood hitting the ground cursed you to wander the earth as a spirit. Genghis Khan reportedly strangled Jamuqa himself, crying as he did so. As for the generals who had betrayed Jamuqa to Temujin, they were boiled in oil.
- A popular item of Filipino history is the Blood Compact (sanduguan in Tagalog, meaning "one blood" or mingling of blood) between Miguel Lopez De Legazpi and the King of Bohol (Datu Sikatuna) in 1565. A contrast to the Filipino revolutionary organization KKK (not that KKK) initiation ceremony where the initiate would cut open an arm vein and use the blood as quill pen ink to write his name on the members' list.
- This was done by the leaders of the seven tribes that would eventually become the people of Hungary. The event is referred to as the Blood Pact, an important historical event.
- In the Chinese historical saga Romance of the Three Kingdoms, the Power Trio of the Kingdom of Shu faction were blood brothers. Specifically, Liu Bei, Zhang Fei, and Guan Yu aka God Of War.
- Vlad the Impaler of Wallachia and Stephan the Great of Moldavia. They were cousins to begin with, and close friends during their childhood, but after losing their respective fathers to treacherous friends and/or family, they made a pact that the first to become ruler will help the other do the same. Vlad was first, and he honored his promise of friendship to the end of his life.