Sworn Brothers

"For he to-day that sheds his blood with me shall be my brother."

— King Henry V, Henry V

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. (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 Sworn 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.

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Examples:

Anime and Manga

• 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.
• The Four-Girl Ensemble of A Certain Scientific Railgun also count.
• In the Fushigi Yuugi series, Genbu Celestial Warriors, Hikitsu and Tomite are the classic pair.
• The manga Gorgeous Carat has Ray and Azura who became sworn 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 Hoshin Engi: Dakki and her two sisters Okijin and Kibi are not related by blood, and are actually different species of Youkai, respectively a fox, a biwa, and a bird, but they are sworn sisters and care for each other as such. Those two are among the very few people for which Dakki show genuine concern.
• Played for Laughs in Jujutsu Kaisen, where Aoi Todo develops a one-sided version of this trope on Yuji after realizing they both like tall girls with big asses. Every time they meet after this, Todo addresses Yuji as "brother". Comedy aside, Todo does help Yuji develop as a Jujutsu sorcerer when they first meet, and later saves him from crossing the Despair Event Horizon during the Shibuya Incident, where he provides critical assistance to Yuji as he decisively defeats Mahito.
• The three central characters of the Koihime†Musou anime are Historical Gender Flips of Guan Yu, Zhang Fei, and Liu Bei, being based off of the Romance of the Three Kingdoms. Like their counterparts, the three are sworn sisters, with Aisha calling Rinrin her little sister and Touka her older sister (although with some reluctance at first).
• The cast of K-On! are one of the rare female versions of this trope.
• Reinhard and Kircheis in Legend of the 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.
  • By extension, Reinhard, Kircheis, Reuenthal and Mittermeyer. Reuenthal went to Reinhard because Mittermeyer was set to be executed by a corrupt noble. Reuenthal swore that if Reinhard helped save Mittermeyer that they would both become his subordinates. Ever since the four have had each other's backs.
• Moriarty the Patriot: The Moriarty crew has all sworn loyalty to William and offered him their lives, titles, and any resources at their disposal (especially their lives, as that's what he tends to ask for in "payment" for his help). Moran and William even exchanged Friendship Trinkets to represent their bond, and many years later, William still carries it around and even asks for it back—and Moran's only comment is that he could offer William something even more useful than a symbol. William refers to their vows of loyalty when discussing how best to organize a functional organization—loyalty like those his companions swore to him is rare and difficult to find.
• In Nura: Rise of the Yokai Clan, the youkai make pacts amongst each other to be sworn brothers.
• 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.
    • Cannot express? How about Sabo falling into an Angst Coma for three days at the sheer news of Ace's death?!
  • While Whitebeard would treat his entire crew as his children, he instead treated Kozuki Oden as a little brother.
  • He also once shared sake cups with King Neptune, much like Luffy and his brothers did, and made good on this by declaring Fishman Island his territory when pirates began to swarm the New World after Roger's execution. In essence, this meant that anyone who caused trouble in Fishman Island would have to answer to Whitebeard himself. No pirate dared to do so for the next 20 years, and he's still remembered fondly by fishmen and merfolk for it.
  • Franky has come to see Señor Pink as a sworn brother after their fight in Dressrosa, breaking into tears when evidence leads him to think that he is dead.
• 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.
• 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.
• Thorfinn and Einar become blood brothers during the second arc of Vinland Saga. As the Norse took these things very seriously historically (see the Mythology section) the two are treated as actual brothers after the declaration, with Thorfinn's mother even declaring Einar is now part of her family.

Comic Books

• The Eagles of Rome: 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. Of course, being teenaged boys, they don't exactly go about it with the expected gravitas.
  Ermanamer: Marcus... You're an idiot. You can't even piss straight, you can't tell the difference between a girl and a sheep, and by some miracle, you saved my life... yet... with my blood, I pledge to be your brother forever.
  Marcus: I, too, swear that I will always be there to hold out my hand if you trip over your dick, brother.
• G.I. Joe: Joe has Snake Eyes and Storm Shadow, who are the equivalent of Sworn 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.
• Corto Maltese: in one story, Corto is forced to become blood brother to join a sect of vigilantes. When the other man presents him the blade Corto scoffs at the notion, finding the ritual useless and likely to give them both tetanus instead.

Comic Strips

• Crabgrass: One of the first arcs, starting with this comic, involves Kevin and Miles becoming this. The fact that they’ve become blood brothers is brought up several times afterwards in the series.

Fan Works

• The Bolt Chronicles: Applies to Bolt and Duke, complete with touching of ensanguined paws, in "The Blood Brother." Bolt's paw becomes infected shortly afterwards, and his blood-oath friendship with Duke ends badly.
• Naruto and Haku become Sworn Brothers in the fanfic A Father's Wrath, swearing an oath in a Peach Garden.
• Harry Potter and the Artificer Legacy: After Harry returns the Sword of Gryffindor to them, the King of the Erdunn dwarves declares him a sworn brother of the clan.
• 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.
• 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."
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.

Film — Animated

• In Puss in Boots, Puss and Humpty Dumpty become blood-and-yolk brothers, pricking their fingers with a pin, then shaking hands.
• 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.

Film — Live Action

• 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 Sworn 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.
• 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.
• Bullet in the Head, John Woo's grimmest and most emotionally devastating movie, is about the disastrous effect of Gold Fever and the horrors of The Vietnam War on the bond between Sworn Brothers, which in John Woo's other movies was all but unbreakable.
• 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.
• In Fantastic Beasts: The Crimes of Grindelwald a crucial MacGuffin in the film is Grindelwald's phylactery, which contains the magical Blood Oath that he and Dumbledore swore to never fight each other. Which is why Dumbledore must rely on proxies like Newt to oppose Grindelwald (and vice versa). Newt's Niffler manages to steal it from Grindelwald during the rally at the end of the film, setting the stage for their future duel in 1945.
• In The Hangover, Alan cuts his hand open to swear blood brotherhood with the rest of the "wolfpack" — who quickly bandage him up and dissuade him.
• In McLintock!, Puma reminds McLintock of their blood-brother bond when they meet at the railroad depot.
• 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.
• In Mongol, two ten year olds (one of whom is the future Genghis Khan) become blood brothers after one saves the other's life.
• The film version of Othello has Othello forcing Iago to perform a blood pact.
• 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.
• Interesting twist in Practical Magic, where a pair of sisters swear blood-brotherhood. This becomes a plot point a couple of times.
• In Sherlock Holmes (2009), 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.
• The slightly bizarre 1953 film Sombrero has a scene where one of the young men slashes his own hand, then his sweetheart's, clasping them together, to ensure they'll never be parted. She's surprised that he knows to do this, and he says:
  You think only gypsies know the ancient ways? This is my land. My people were here before Cortez. Our gods still live in these mountains. Listen, and you will hear their voices.
• In Son of Rambow, Lee Carter decides he and Will Proudfoot should become blood brothers after he saves Will from drowning.
• 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.
• 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.
• Wild America: Even though Marty and Mark are actual brothers, they prepare for their road trip by going through a painful ritual that involves rolling a drop of molten metal down each of their backs, stamping on the drops with their shoes, then picking them up and mashing them together while they shake hands.
• 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.
• The World of Henry Orient has a Gender Flipped version; Val, a Stalker with a Crush on the title character (a third-rate concert pianist) enters into a Blood Oath with Gil, her best friend, in devoting their lives to pursuing Henry (without ever meeting them). They prick each others' fingers with a needle, and then after they take the oath, they realize how much their fingers hurt.
• There's one 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.

Literature

• 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.
• 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.
• 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.
• 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.
• In Citizen of the Galaxy Thorby Baslim is adopted by the Free Traders by having a knife jabbed into his shoulder and his blood rubbed into the spaceship floor, with the words "our steel is in your blood, your blood is in our steel".
• In Darkness Visible Marsh and Lewis definitely qualify as this. Once they stop hating each other, that is...
• In the Deryni trilogy The Chronicles of King Kelson, Kelson Haldane and Dhugal MacArdry swore an oath as blood brothers when they were boys and Dhugal was fostered at the Haldane court. It becomes a major factor in their relationship, as they truly meant the oath and treat each other as brothers.
• 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."
• Emberverse: The anamchara ritual has this effect. Unlike most takes on this trope, it does not preclude romance.
• 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 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 Grandmaster of Demonic Cultivation: Mo Dao Zu Shi, Lan Xichen, Nie Mingjue, and Jin Guangyao become sworn brothers after the Sunshot Campaign, forming the trio known as the Venerated Triad.
• 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.
• Mercedes Lackey's Heralds of Valdemar series:
  • Tarma and Kethry of the Vows and Honor trilogy are regarded as "oath-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 crescent-shaped scars. Later they wear matching rings. In Tarma's culture oath-siblings are regarded as Heterosexual Life Partners and such a bond is more highly respected than most marriages, even conveying a bit of Mindlink Mates. When Tarma takes Kethry home, xenophobes treat the joining of one of their own and an outsider as a Maligned Mixed Marriage and say that Kethry must have used her magic to fool Tarma. It takes divine intervention to settle them. Later, Kethry's children are considered also Tarma's by blood.
  • 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.
• 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 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.
• 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.
• Judge Dee's three lieutenants, Ma Joong, Chiao Tai and Tao Gan, consider themselves and refer to each other as Blood Brothers.
• Language Arts: Charles and Donnie invent their own version that involves swapping the band-aids on their scraped knees.
• Li Cunxin and his friend The Bandit became blood brothers in the autobiography Mao's Last Dancer.
• Nightfall (Series): A darker example: vampires can become blood brothers after drinking each other's blood.
• Orphans of the Sky: After resolving to take over the Ship, reveal the true nature of the world to the Crew, and unite Crew and Muties to finish the Trip, the main characters stab themselves in the upper arms and press their shoulders together to mingle their blood while swearing an oath of companionship.
  "Blade for blade!"
  "Back to back!"
  "Blood to blood!"
  "Blood brothers, to the end of the Trip!"
• 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.
• 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 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.
• In The Shadowhunter Chronicles two Shadowhunters can take an oath to become parabatai. If they do this they swear to fight together for the rest of their lives. Most parbatai are really close. Romantic love between parabatai is forbidden though. There are multiple examples in the series.
  • The Mortal Instruments has Jace and Alec who are also adoptive brothers. They have fought side by side many times and always have each others backs.
  • The Infernal Devices has Will and Jem who have a really strong friendship despite their completely different personalities. Even when they fall in love with the same girl, it doesn't damage their friendship.
  • The Dark Artifices has Emma and Julian. They were childhood friends who only fot closer after the death of both of their parents. However their relation is not strictly platonic, as Emma and Julian start to develop feelings for each other, which is strictly forbidden. Their parabatai bond eventually gets broken at the end of the series.
  • At the end of Tales from the Shadowhunter Academy, Simon becomes a Shadowhunter. This means that he and his childhood best friend Clary can become parabatai.
• 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.
• The Silerian Trilogy: Shallaheen Silerians commonly adopt family through blood pacts, not just siblings but any kind of relations. Josarian and Tansen become blood brothers early in the first book. Earlier Tansen had an adopted blood father too.
• 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!
• King Robert Baratheon and Lord Eddard Stark of A Song of Ice and Fire would certainly qualify, as would Theon Greyjoy and Robb Stark.
• 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.
• 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.
• 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.
• In the Tortall Universe, the Bazhir tribes work in this space a lot. Becoming a member of a tribe, as portrayed in Song of the Lioness, requires an outsider to share blood with a tribesman in a ceremony. The spiritual leader of the Bazhir, the Voice of the Tribes, can pass this position on to a successor through intensive teaching and another ritual involving making a much larger cut and binding the two's arms together. Even adoption requires this.
• Max and Ephraim in The Troop. Friends since they were babies; they decide to do this to cement their status as "Forever Friends."
• 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.
• Wagons West: Both Sam Brentwood and Whip Holt are blood brothers to the Cherokee, Stalking Horse. In Independence!, when Abe Ellis almost killed Stalking Horse due to a hatred of Indians, Sam told Abe that had he succeeded, Sam would have been obligated to kill Abe in return.
• Carmilla and Fey, in the Whateley Universe, even going so far as making a blood pact.
• An Aiel ritual in The Wheel of Time can make you first-brothers or first-sisters - it's assumed you and your prospective sibling will be the same gender - if you're not already that by birth ("first-brothers"/"first-sisters" is just the Aiel name for what we call brothers and sisters; cousins are "second-brothers"/"second-sisters"); the ritual is shown in detail when Elayne and Aviendha go through it to become first-sisters. The climax involves a Wise One who can channel using a weave that makes the pair in question experience being in the Wise One's womb and born together. There are other parts to the ritual before that, including a phase where they say out loud everything they resent about each other and get into a tussle (it's mentioned that more men than women decide not to go further at that point). Becoming first-sisters is also necessary for two women who are going to marry the same man, though that's not the only reason two women might undergo it.
  • 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. This makes sense, as the Borderland nations keep the rest of the continent defended from the Blight and in-fighting amongst them would be disastrous.
• 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.
• 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 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."

Live-Action TV

• On The Andy Griffith Show Opie and a new boy named Trey become blood brothers, only they use barn paint instead because they don't want to get an infection.
• The Easy Company in Band of Brothers evolves into True Companions by stacking blood brotherhoods one after another.
• Played with in the Buffy the Vampire Slayer episode "Blood Ties". Although Dawn, who was transformed from a mystical Key into Buffy's little sister and retroactively inserted into everyone's memories, is confused about her own existence, 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.
• 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!"
• 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.
• Game of Thrones:
  • King 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.
  "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."
  • A Dothraki khal and his bloodriders share everything until the day they die.
• 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.)
• 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.
• Mac and Dennis on It's Always Sunny in Philadelphia refer to themselves as "blood brothers".
• 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.
• 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.
• The Princess Wei Young: After their Blood Oath Jun Tao declares that she and Bai Zhi are sisters. Xin Er also says that Jun Tao, Bai Zhi and Zi Yan are her sisters, though there's no Blood Oath involved in this case.
• Punky Brewster: Punky, Cherie and Margaux felt disgusted at the notion of using blood so they instead became "ketchup sisters".
• In Seinfeld, Kramer declares himself and Jerry this after he donates three pints of blood to save Jerry's life. By the end of the episode, Jerry has been injured again and received an additional blood donation from Newman.
• 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.
• 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 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.
  • The Klingons are very big on this. The legendary Dahar masters Kang, Koloth, and Kor formed a blood pact which included Trill Ambadassador Curzon Dax and carried over to Jadzia Dax. Worf and Martok also become blood brothers shortly after escaping a Dominion prison camp.
• Velvet: How Alberto and Mateo regard each other.

Music

• 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.
• 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.
• Bruce Springsteen has a song named Blood Brothers which fits this trope perfectly.

Mythology

• 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.

Professional Wrestling

• 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 The Wild Samoans, The Rock (Dwayne Johnson), the late Rodney Anoa'i (a.k.a. Yokozuna), Solofa Fatu (Rikishi), The Tonga Kid, Eddie Fatu (known as Umaga), Joe Anoa'i (Roman Reigns), and Josh and Jon Fatu (known as Jimmy and Jey Uso).
• 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.

Roleplay

• 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.

Tabletop Games

• 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".
• 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).
• 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.
  • White Dwarf magazine #64 article "Spells for Friends". The spell Blood Brothers mingles the blood of two beings. The beings can communicate telepathically over any distance once per day, they always know the distance and direction the other is, and if one dies, the other will know about it and where their corpse is. Each gains combat advantages when they fight together.
• All Space Marines ever in Warhammer 40,000. They even call each other "Brother", constantly, though this may be as much their somewhat 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.

Theater

• The musical Blood Brothers, obviously, complete with Mickey and Edward making a Blood Oath. It goes very, very badly once they find out that they are indeed brothers, Separated at Birth.
• 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.

Video Games

• 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 Call of Duty: Modern Warfare 3 titled "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.
• Dynasty Warriors 8: Empires allows the player to have up to two other officers become sworn siblings with the officer they're playing as. In gameplay, this means the chosen officers will always be in the same faction as you, so if you defect, they will defect with you, or if you decide to steal territory from your ruler, your sworn siblings will be guaranteed to side with you. If one of your sworn siblings is your current ruler, then you can't betray them, no matter what.
• The Elder Scrolls V: Skyrim has this dynamic with the Companions, who are "brothers and sisters in honor", and who refer to each other as "Shield-Brother" and "Shield-Sister" depending on the gender. Apart from the ceremony that welcomes you into the Companions, there's also the blood-pact that's required to become a member of the Circle within the Companions, and which turns you into a werewolf.
• 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.
• Eliwood and Hector from Fire Emblem: The Blazing Blade, right down to the literal blood pact they made as children.
• 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.
• 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 an entire city filled with our relatives. He needs to die."
• In Knights of the Old Republic II: The Sith Lords, a dark side player character can become this with the berserker Wookiee Hanharr. Notable as this may be the only positive relationship either of them have.
• The Legend of Zelda:
  • 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.
  • The Legend of Zelda: Breath of the Wild has the three Goron Blood Brothers who spend all their time training their strength and endurance. Link can become the fourth Blood Brother by training with them.
• Like a Dragon is, unsurprisingly, full of examples.
  • Series protagonist Kazuma Kiryu swore brotherhood to his childhood friend Akira Nishikiyama at a very young age, and the two stood by each others' side come hell or high water for nearly forty years until Nishiki's Face–Heel Turn.
  • Goro Majima was the sworn brother of Taiga Saejima, and they were commented on as being uncommonly close, even by that standard. Majima endured over a year of hellish torture and gave up one of his eyes rather than sell his brother out.
  • Shigeru Nakahara, the leader of the Ryudo clan in Ryukyu, insists on becoming sworn brothers with Kiryu as a sign of respect after Kiryu saves his adopted daughter from kidnappers, not realizing who Kiryu is. He has a minor Oh, Crap! moment after he realizes he just inextricably tied his fate to that of the Dragon of Dojima.
  • Daigo Dojima and Yoshitaka Mine were also sworn brothers and very, almost inappropriately, close. In fact, Mine's obsessive attachment to Daigo (in conjunction with a whole slew of unresolved childhood issues) fuels much of the conflict in Yakuza 3.
  • Ichiban Kasuga considers Masato Arakawa, the wheelchair-bound son of his boss Masumi Arakawa, to be both his brother and best friend. Masato, however, sees Ichiban as little more than a bootlicker hired by his father to be a caretaker and treats him with barely hidden contempt. It's only until the very end of Yakuza: Like a Dragon, when Ichiban tearfully talks Masato out of taking his own life, that Masato realizes that Ichiban was the only true friend he ever had.
  • Futoshi Shimano and Tsukasa Sagawa are oath brothers by the time of Yakuza 0, even though the former is from the Tojo Clan and the latter is from the Omi alliance. This is much more a political oath than a bond as they don't care that much for each other, Shimano has a similar oath with his former boss Sohei Dojima andthey have actively worked against each other in the past.
• Solid Snake and Otacon in the Metal Gear series.
• 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. The Blood Brothers can also appear to defend each other if one engages in a fight with you.
• Eventually, in Planescape: Torment Dak'kon does the Pronouncement of Two Deaths as One with you, effectively making you Blood Brothers until death.
• 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.
• In Warcraft, Thrall, Cairne, and Vol'Jin consider each others brothers through 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.
  • Tirion Fordring (a Human) and Eitrigg (an Orc) also consider one another blood brothers after Tirion risked his life to prevent Eitrigg's execution in Stralthome.

Webcomics

• 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]
• 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.

Western Animation

• 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.
• 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.
• 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.
• 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.
• Parodied in The Simpsons when Bart and Milhouse became "spit brothers", complete with spitting in the hands and clasping them.
• 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.
• Star Trek: Lower Decks: In "Envoys", Ensign Mariner mentions to Ensign Boimler that she and K'orin are blood-bonded.
• On Young Justice (2010), Beast Boy and Miss Martian refer to each other this way after she gave him a blood transfusion.

Real Life

• 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 three founders 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.

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