In a way this is the initial premise of Sakende Yaruze! but ends up not holding true. Because Shino is his father Nakaya (at seventeen) seeks him out hoping to form a familial relationship, and they do begin to grow close, but they're often at odds with one another and how they are supposed to act. In the end Nakaya decides that though he has a claim to Shino because of their blood relationship, it would go against his dad's happiness to force Shino to reject his Love Interest Tenryuu, so Nakaya gives up his stake in the affair and moves out, not wanting to be in the way. Their familial bond is important, but not overriding.
Subverted in Blood+. One may expect Saya to abandon her adopted brothers after discovering she's a Chiropteran and live with them. Instead, she decides to stay and fight as she feels the former are more important to her.
Dragon Ball Z is a notable aversion. Goku and Raditz never shown any affection for one another. Goku was willing to spare Raditz as an act of mercy, but it turned out to be a trick, almost costing him the fight. After Raditz is killed, he is rarely ever mentioned again.
Fist of the North Star, Kenshiro having been on the rare receiving end of a Curb-Stomp Battle with Souther, finds himself on the desert and loses consciousness only to be rescued by Raoh, his elder brother and the Big Bad (who himself was in the middle of a recovery from his last fight with Kenshiro), nursed back to health. Raoh, alongside Toki later follows Kenshiro for his rematch with Souther, slaughtering any of Souther's men that happens to be in the way. Toki sums it up perfectly:
Toki: We elder brothers of Hokuto will not forgive those who block Kenshiro's path.
This is one of the reasons why Gil never abandoned his younger brother Vincent in Pandora Hearts, even though he was constantly maltreated because of Vincent's birth condition.
In Soul eater, Crona uses hir madness to prevent Maka and Black★Star from matching soul wavelengths with their weapons, but Maka still manages to wield Spirit. Spirit explains to confused Crona that the bond between a parent and child can never be broken. However, it is also stated that while parent-child resonance is stable it may not be as powerful as resonance between individuals with different backgrounds and characters.
Robin Hood comes to his death when he trusts a prioress because she is his cousin.
When Connor Hawke showed up in Green Arrow, that Oliver Queen did not want to deal with him was regarded as a grievous flaw; Connor was a stranger, but also his son.
Connor wasn't really a stranger at that point, though. Ollie's anger and refusal to want to deal with Connor at that point stemmed from the fact that Connor had concealed the fact that he was Ollie's long-lost son. He had introduced himself to Ollie as a fan of Green Arrow and Oliver had no clue that his new sidekick was his long-lost son until the fact was accidentally dropped by a Parallax-possessed Hal Jordan. Given that Ollie was a wanted fugitive at the time, his paranoia about Connor lying to him because he wanted something or was working with the people hunting him is understandable if not particularly justified.
In RainbowDoubleDash's Lunaverse, Night Light refuses to believe that Twilight could have done anything wrong. He sees his daughter's fugitive status as being entirely Trixie's fault - it's actually both of theirs - and is entirely willing to let Ponyville remain in ruins to get back at the latter.At the Grand Galloping Gala, Ditzy calls him out on it by using her own motherhood to give herself the high ground and deflect his attempts to use this.
In The Masks We Wear, Zuko refuses to betray his father despite the fact that he (Ozai) burned him.
Played for drama by The Kids Are All Right. Joni and Laser meet the sperm donor who is their biological father, but the sperm donor's attempts to build a relationship with them and their mothers cause serious family friction and nearly break up the mothers' relationship with each other.
Star Wars: Luke doesn't have to join Darth Vader, but knowing that he's his father puts anguish in what would be a simple decision — and then he wants to pull him back.
This trope is also what saved Luke from an agonizing death from force lightning at the hands of the Emperor. Watching his son get electrocuted was the final straw that motivated Vader to toss the Emperor down the chasm.
The Avengers: Thor's attitude toward his Ax-Crazy brother Loki is a mixture of anger, disappointment, and protectiveness. He discourages the other heroes from taking custody of Loki so he can settle his score with himself, yet every time keeps trying to get Loki to turn back toward good again, even after Loki drops him 30,000 feet in a steel cage. Thor's attitude is even more impressive considering Loki is a Frost Giant runt that Odin raised as his own and they're not even related, or even the same species. Thor doesn't give a damn and says as much to Loki, but for Loki himself it's a major sticking point.
Thor: Have care how you speak! Loki may be beyond reason... but he is of Asgard, and he is my brother.
Referenced and subverted in The Players Club. When Diana finds her cousin, Ebony, in bed with her boyfriend, she tries to attack Ebony, who hides in the bathroom. Diana then gives a heartfelt speech about how much she loved her cousin and how she thought blood was thicker than water but was apparently wrong. She then pretends to leave...and punches Ebony in the face when she finally comes out of the bathroom.
In Lockout, another prisoner questions the riot leader Alex why he doesn't kill the obviously psychotic prisoner who is clearly a liability because of his homocidal urges. Alex responds that it's because that guy, Hydell, is his brother. This tragically ensures his downfall, as Hydell kills Alex himself when he refuses to put up with Hydell's lunacy anymore.
From Dusk Till Dawn. Seth Gecko, a ruthless criminal himself, is quite aware that his brother Richie is a psychotic rapist and serial killer. When Seth discovers Richie's latest crime of killing their only hostage he's incredibly disturbed but forgives him nevertheless, promising that they'll have a better life together in Mexico.
In Cold Comfort Farm Flora explains this trope thusly when explaining her plan to live off her relatives: 'I am only nineteen, but I have already observed that whereas there still lingers some absurd prejudice against living on one's friends, no limits are set, either by society or by one's own conscience, to the amount one may impose upon one's relatives'.
In Edgar Rice Burroughs's Gods Of Mars, when Carthoris learns that the man he had met only days before is his father, and John Carter convinces him of it by asking after his mother, Carthoris jumps to embrace him and weep Manly Tears. Then, by his own account, he had long wanted to be worthy of his father.
In The Chessman Of Mars, on learning that A-Tor is the son of Haja of Gathol and so his cousin, Gahan of Gathol is immediately interested in him, and assures him that if he had made it to Gathol, being her son would have assured him a welcome.
In L. M. Montgomery's A Tangled Web, we are told, in the Back Story, a mere family feud that keeps relatives from speaking to each other does not keep one of them from punching a man for insulting the other side of the family.
In The Dresden Files, Thomas Raith takes this seriously, partly because Daddy Raith raised his children that way to control them, but partly because he truly believes it. After he reveals their connection to Harry, to explain why he looks out for him, Harry returns it. Which is interesting because the rest of the Raiths do not act on it — in spades.
Harry himself goes to ridiculous lengths to protect and help people he considers family as well as the few people who are actually his blood relations. And he also often goes out on a limb to protect other families, especially the Carpenters. Having grown up as an orphan probably has something to do with it.
Lara Raith is shown to be very protective of her family, especially her youngest siblings Inari and Thomas. The one exception being Papa Raith after Harry Dresden tricks him into revealing his true feelings for his children while she was listening...
In the Discworld books the Oggs are constantly feuding with one another but woe to any hapless interloper who insults an Ogg in front of another Ogg, in which event every single Ogg will turn on them.
In Rick Riordan's The Last Olympian, Nico's argument to Hades: whatever the Olympians had done to each other, they were family. (Though, technically, that's Ichor Is Thicker. But candy is dandy.)
Earlier, Percy and Tyson deepen their bond by finding out they are half-brothers. (Not that they get along with all of Poseidon's other sons.)
It's played with, though. Tyson and Percy were already friends, it's just that finding out that one of your best friends is your brother and a cyclops makes things a bit...awkward between them. It doesn't help that Percy is teased relentlessly about it. Subverted when the Big Bad of that very book is Polyphemus, a fellow son of Poseidon, who Tyson and Percy open a can of whup-ass upon.
In Lois McMaster Bujold's Brothers In Arms, Miles Vorkosigan's immediate interest in his brother/clone Mark is tempered by the events of the novel. But later in the series, both Miles and his parents evince interest in Mark based solely on the blood connection, and he does end up on Barrayan among the Vorkosigans.
In Dante's Divine Comedy, the next to last circle of Hell holds those who betrayed their own kin.
Even his noble motive — not disrupting their lives with their new parents — does not protect Kolea from criticism for not letting his two children know that he is their father.
In Blood Pact, Eyl tells the witch that she is his sister and he does not want to have to force her to do something.
In James Swallow's Warhammer 40,000Deus Encarmine'' and ''Deus Sanguinius, Rafen looks for Arkio among the other Blood Angels who have arrived, because they are siblings, despite Sachiel's rebuke that all Blood Angels are brothers. When Arkio appears to be Sagninius reborn, Rafen feels bitter Conflicting Loyalty, others seek out Rafen because he is his brother, and he is allowed more leyway for his doubts. It also makes the threat, and reality, of their Cain and Abel clash all the more bitter.
In The Book of Atrix Wolfe, Burne can not bear the thought of losing Tanis, his only living relative.
In The Forgotten Beasts of Eld, the sorceress Sybel, who has no interest in the company of other humans, agrees to keep the baby Tam safe from those hunting him only because he's related to her mother.
In The Riddle Master Trilogy, when Morgon disappears on his quest to solve the riddle of stars, his timid younger sister Tristan decides she has no choice but to set off to find him, to the dismay of everyone. Also, one of the shapeshifters from beneath the sea declines to attack Raederle when he recognizes shifter blood in her.
In L. Jagi Lamplighter's Prospero Lost, Miranda is anxious about her brothers and sister, becuase they are immortal; Mab points out they are immortal because of the Water of Life she gives them; Miranda justifies it because they are her family. To put it another way: if Miranda didn't believe this, the books would be a lot shorter.
Rob Thurman quite likes this trope. In her novel Chimera, Stefan Korsak would move Heaven and Earth to find his kidnapped little brother, Lukas. In the Cal Leandros series, Cal and his older brother Niko would do anything to protect each other. Threatening either one of them in the presence of his brother is likely to be met with a swift, painful, and possibly lethal response.
The Stainless Steel Rat: Jim's sons override his scruples on leading them into a life of crime on the grounds that saving their mother from the income tax people is a good cause.
In Tanith Lee's The Dragon Hoard, Onga points out that Jasleth lied to them not on his own behalf but because of his family, and everyone agrees it's a good reason.
In Adrian Tchaikovsky's Empire in Black And Gold, Stenwold is outraged when his niece is betrayed to the empire by another relative of hers. He still doesn't want to be a kinslayer, though. Fortunately, Tisamon's willing to kill the man for him.
In Jack Campbell's The Lost Fleet, Geary looks up another man in the fleet named Geary to find whether they are related. Other characters also base acts on blood relations.
A Murder Is Announced features twin sisters who have been Separated at Birth, don't know they're sisters, and one of them actually dislikes the other. However, once they realize the relationship, they develop a sense of family solidarity and one of them (the one who disliked the other) goes so far as to lie to the police for her sister's sake.
In Teresa Frohock's Miserere: An Autumn Tale, Catarina criticizes Lucian for protecting a stranger from her, his own sister.
In Gene Stratton Porter's The Song of the Cardinal, the she-cardinal suffers because of a separation in the migration
She was so frail and weak she lost her family in migration, and followed with some strangers that were none too kind.
In Devon Monk's Allie Beckstrom book Magic to the Bone, Mama tells one of her Boys he's bringing trouble on his family, he argues that he could get them money and power, and Mama counters he should not be ashamed of his real family.
In Poul Anderson's "Say It With Flowers", Ulstead, asking for news of a battle, tells Flowers that his nephew was on one of the ships.
In P. G. Wodehouse's Jill The Reckless, Wally tells Jill that her father had gotten him a job — he couldn't have taken better care of him had he been a blood relation.
Trapped on Draconica: Zarracka invokes this whenever she's at Daniar's mercy but inverts when their positions are reversed. Interestingly when Daniar has had enough with Zarracka and the third sister stops her, it's not out of blood loyalty to Zarracka but because she doesn't want Daniar to kill someone in anger.
Seen in Harry Potter, and evident primarily with the Blacks, although occurs in several other family as well. Overlaps with Family Honor in many cases, but not always.
The term 'blood traitor' is often applied to wizards (primarily purebloods, but not necessarily) who 'betray the family' by going against their ideals. It is considered a highly derogatory term, and is comparable to disownment. It's also worth noting that this 'obedience to family' is a driving force amidst many of the Death Eaters (eg. Regulus, the Malfoys), and seems to be a major factor in pureblood culture. 'Blood traitor' is also used in a more general sense, to donate those who have gone against the perceived 'societal principles of wizardkind' as well, presumably as a derivative of the above.
In Seanan McGuire's InCryptid novel Discount Armageddon, Verity recounts how cryptids are either loners or passionate adherents of this trope.
Rickard Karstark evokes his family's centuries-old common ancestry with the Starks to warn Robb of the evil of kinslaying when he threatens to execute him for treason. It doesn't work.
Tyrion has to flee the realm after being falsely accused of murdering his nephew Joffrey, and later actually murdering his father Tywin (partly in revenge for the false accusation).
Roose Bolton strongly suspects that his legitimate infant son was killed by his adult bastard son Ramsay Snow, but refuses to do anything about it since the only possible punishment for such a crime would be death, and then he'd be guilty of the same crime (not to mention childless).
In Seanan McGuire's October Daye novel Ashes of Honor, Chelsea is, by the end of the book, calling for her father for help, even though he had only learned of her existence days before, and she had never met him until after. (True, he does help her with her out-of-control magic in those days.)
In Poul Anderson's "Time Lag", Elva's rescuers, realizing she's a Fish Out of Temporal Water, quickly assure her that her son is alive, though old; that one of her rescuers is her grandson; and that he has a son of his own, before going on to say that her people are eager to welcome her home. Her grandson takes her hands as soon as she is told.
In Andre Norton's Ice Crown, there is a blood connection between the princess and Nilas Imfray, which the princess thinks important.
In Andre Norton's The Zero Stone, Jern's mother reveals after his father's death that he was a duty child, an embryo sent to be adopted and raised in their family, and therefore everything must go to his brother because he's not this. Jern himself is infuriated by it because it means he's not his father's blood; later, he consoles himself with the thought that in mind, he inherited more than his father's blood son and daughter.
In Julie Kagawa's The Iron Daughter, Meghan finds a photo of herself with her putative father. She recognizes what happened to him. Despite having lost her memories of him, and knowing there was actually no blood connection, she thinks she should rescue him.
In Pact, Blake and Rose Thorburn struggle with this trope as children of a Big Screwed-Up Family, coping with the dysfunctionality in different ways. Blake runs away, while Rose joins in with efforts by her parents to discredit or otherwise harm her cousins, finding herself friendless and without allies as the family rips itself apart. Blake, meanwhile, finds himself unable to disconnect himself from the family and returns when his grandmother is dying to hear her verdict on the inheritance and tell her what he thinks of her.
Gabriel Lightwood from The Infernal Devices, puts strong emphasis on staying loyal to family. At the end of The Clockwork Prince, Gabriel chooses to stay with his father while his older brother Gideon deserts him for the Institute. In The Clockwork Princess, he finally understands that he was wrong to trust his father so much.
Alfred Hitchcock: I presume that story was intended to illustrate that blood is thicker than water. I always find it heartwarming to see a family standing shoulder to shoulder in the face of adversity. Unfortunately, the authorities were not thrilled by this sight, and were seen tossing about such phrases as, "obstructing justice," "accessory after the fact," "murder in the first degree."
Captain Kathryn Janeway: There's an old saying: "Blood is thicker than water". It means that the ties of family run deeper than any other kind of relationship. We'll often do things for members of our family we'd never dream of doing for anyone else.
Blood Over Water interprets this a little differently: Are you more loyal to the friends that treat you like family, or to the water bottling company that will pay you hundreds of thousands of dollars to shoot them dead so they don't rat the company out? Also, that blood is shed over water.
Narrator: [narration as John 'John Boy' Walton, Jr. reading from his journal] In those grey and grinding days of the Depression we often found comfort in the old familiar proverbs. We knew that in unity there was strength, that blood was thicker than water, that to err was human, and to forgive, divine. Usually we never examined these truths too closely, but in the autumn of 1934 I discovered, through pain and remorse, just how profoundly true they were.
The Wire: Avon Barksdale will do anything for kin. Stringer Bell... Not so much.
Stringer Bell: "But there go a life that had to be snatched, Avon (...) Twenty years above his fucking head. He'd flip, man! They got you, me, and Brianna! No fucking way, man! Hell, no! Now, I know you family, you loved that nigga, but you wanna talk that 'Blood is thicker than water' bullshit, you take that shit somewhere else, nigga! That motherfucker would've taken down the whole fucking show, starting with you, killer!"
Comes up frequently in The Sopranos, during Tony's confrontations with his mother, uncle, and nephew at various points. A particularly notable story arc finds him agonising over giving up his cousin Tony Blundetto (guest star Steve Buscemi) to be killed by fellow crime boss Johnny Sack. Blundetto has provoked this by killing one of Sack's men, but Tony (S) knows his cousin would have a drawn out, torturous death. In the end he compromises by shooting Blundetto himself, quickly and painlessly.
In the Doctor Who episode Planet of Fire, Turlough is immediately interested in Malkon, and when Malkon is injured, Turlough's ready to kill. The Doctor says it would do no good, whereupon Turlough reveals that they are brothers. And this when they were parted so young that Malkon has no memories of Turlough. Later, Turlough, on seeing the healing gases from the volcano, carries his brother into them when everyone else is afraid of being burned.
In The Mutants, Varan choses his own son for the assassin, which he cites as proof of his absolute reliability.
His nephew Hughie gives it an Ironic Echo in "The Return of Hughie Hogg", in which Boss Hogg signs over all his possessions to Hughie (as a tax dodge or something) and Hughie then refuses to give them back.
On Dallas, whenever a group of non-Ewings was ready to give JR what he had coming, Bobby would usually stand up to them and talk them down, despite the fact the JR messed with Bobby's personal and professional life more than everyone else combined.
The trailers for the new series also have this gem from (who else?) JR: "Blood may be thicker than water, but oil is thicker than both."
Angel: Subverted with Angel and Connor. Later played straight in the Season Four finale when Angel agrees to mind wipe his team (and, in fact, the world) in exchange for saving Connor's life. Wesley is rightly steamed when he uncovers this. And like it or not, Darla is the closest thing to family Angel has. Even his team comes second.
On soaps, it's common for characters to quickly bond with their newly discovered family and completely forget about the non-blood relatives they grew up with.
Sanford and Son: Lamont is very patient with Fred's plots and schemes due to the father son relationship. During Season 3, Redd Foxx goes on strike and its written that Fred is visiting relatives in St. Louis. Grady goes to watch the house for Fred. Lamont doesn't extend his tolerance to Grady and is much more openly angered by Grady's plots than he is with Fred's.
Subverted in The West Wing. The senior staff are not related, but are so tight-knit that when it comes to defending one of their own, even at political cost, they explicitly invoke this trope by comparing their friendships to flesh-and-blood family ties in order to explain why throwing a co-worker under the bus is not an option. (Bartlet has actually point-blank declared that the senior staff are part of his family, and shall be treated as such).
In Merlin, the reason for Arthur's trust in his Obviously EvilUncle Agravaine is handwaved by the show with this excuse; that he is Arthur's mother's brother, and therefore trustworthy.
In season three of Justified, Detroit mob boss Theo Tonin raised Robert Quarles as an adopted son. However, when Quarles pointed a gun at Theo's biological son Sammy, Theo did not hesitate to put a bounty on Quarles' head and send mooks to kill him.
Days of Our Lives is fond of this one. In addition to all the myriad ways characters are related due to marriage and divorce and remarriage and all the half-/step-siblings running around and the ways in which they use those ties to take advantage of one another, it's often a good test of paternity: when a man is unable to comfort the infant he's raised from birth, but another, seemingly random man is able to stop the baby from crying in an instant, you can bet dollars to donuts the second man is secretly the biological father. It's as if being blood relatives gives you magic powers over fussy children.
Although the titular character's family in Malcolm in the Middle are dysfunctional, obnoxious, fight constantly, and make each other miserable, it is by far the most important thing in their lives, which is a recurring theme of the series. Despite their dysfunctionality, the characters can always count on one member of their family or another to pick up the pieces of their failures. In the finale, it is revealed that they have all been scheming to make sure Malcolm fulfills his potential and becomes successful for years, because they know he is the only one of them who has the capacity to do great things. Malcolm in turn, dedicates his valedictorian speech to them and dedicates his life to making them proud, even though his mother brutally screwed him over in order to force him to go to Harvard and aim to change the world rather than waste his genius on a high-paying corporate job.
Subverted in the story Dewey tells his brother Jamie. In the story, Dewey and Jamie decide to defeat their evil parents and free their brother Francis from their clutches. At the end of the story, Dewey abandons Jamie and leaves him to be captured. The story ends with Dewey's moral: everyone in this family would turn on you at the drop of a hat.
The family from Married... with Children fight and crap on each other all the time. But God help the outsiders who come after, mess with, or screw over one of them, for they shall invite the full white-trash wrath of the Bundys upon them.
In Battlestar Galactica (Reimagined), John's mother is extremely dissapointed in her Cylon son and how many terrible things he has done out of pettiness and rage at his parents for giving him a human body. She calls her petulant son out on his jealousy and sadism, but despite all of John's crimes like fratricide, genocide, and even raping her, says that he isn't broken and could still be redeemed if he accepted what he was. She states she still loves him because she made him.
The Bee Gees: In the early 1970s, the three elder Gibb brothers temporarily disbanded due to creative and personal differences. Realizing they had a good thing going and the fact they were brothers they realized they had to shore up their relationship. They did, and by the end of the decade, music was never the same again.
For Barry, Robin and Maurice's little bro', Andy, literally as he had a No. 1 pop smash in March 1978 with "(Love Is) Thicker Than Water."
When Theseus comes to Athens, his step-mother, Medea, tries to poison him, but Aegeus recognized the Orphans Plot Trinkets he had left for Theseus, saves him, and exiles Medea — although he had never even seen his son before.
King Midas finally learns his lesson not when he can't eat for turning food to gold, but when he turns his daughter to gold.
Subverted by Ariadne, who betrays her father, King Minos, and helpes Theseus kill the Minotaur, who is her half-brother.
Once again subverted by Medea, who helps Jason steal the Golden Fleece from her father. She also kills her own brother and scatters his remnants to make it easier for her and Jason to escape.
One of the central tropes in Greek theater, especially the plays of Aeschylus and Sophocles. Often dramatized as a conflict between "familial piety" (upheld by the Furies) and devotion to the gods (particularly Apollo in these texts). Does morality mean staying loyal to your family or doing what the gods (or reason) dictate?
The reason Antigone cites for burying her brother though it is against the law is precisely that he's her brother; "filial piety" demands that one put the just claims of one's relations above the law.
Aeschylus' Oresteian trilogy pretty much fits the above description to a tee. It chronicles Orestes' attempts to rid his family of a longstanding curse on the orders of Apollo. Unfortunately for him, getting rid of the curse involves killing his mother (who had killed his father who had killed his sister...yeah, it's that kind of story); which of course brings the Furies down on him in full force.
This serves as a rather hilarious Deus ex Machina in A Funny Thing Happened on the Way to the Forum. After Pseudolus' attempt to save Philia from an unhappy Arranged Marriage to Miles ends in an Epic Fail and it looks like he's in big trouble, Erronius shows up and notices that Miles and Philia are wearing rings which mark them as his long-lost children. Philia's betrothal to Miles is obviously nullified by the unexpected revelation that they're siblings, and she is able to marry Hero, resulting in Pseudolus being granted his freedom.
Call of Juarez: Bound in Blood is ALL about this trope (hint: the title is a clue). The whole story is basically about the three McCall brothers dealing with their differences in all the wrong ways until the very end. In fact, the tagline of the game could be "We are a family".
The loyalty missions in Mass Effect 2 are supposed to resolve the deepest internal conflicts and motivations of their respective characters. Not surprisingly, half of them revolves around family matters: Grunt finds a tribe for himself; Jacob deals with his Disappeared Dad; Miranda rescues her twin sister; Samara tracks down her daughter; Tali has to deal with the blowback of her father's covert misdeeds; and Thane tries to return to his paternal duties.
Then there's Legion, who may not necessarily have blood, but in a weird way his loyalty mission does involve his family.
And it was hardly the first time BioWare played that card. The "messenger" quests in Knights of the Old Republic serve much the same function. Carth's Dark Jedi son, Bastila's mother, Mission's deadbeat brother, the utter clusterfuck on Kashyyyk regarding Zaalbar's family...And while it probably isn't blood related, the Mandalorian concept of "family" would put the Jagi and Canderous on this, too.
The original Dragon Age: Origins has a sidequest which subverts this. Alistair knows he has a half-sister and he's always wanted to visit her, but when he does, she wants nothing to do with him and denounces him for trying to intrude on her life without giving her financial support.
Especially nastily averted with Morrigan and Flemeth. Blood ties are fine and dandy but they're not going to dissuade Flemeth from stealing Morrigan's body or Morrigan from having Flemeth killed. (It's not clear even to Morrigan whether Flemeth is Morrigan's biological or adoptive mother, but Morrigan considers this detail irrelevant.)
The City Elf Origin has got an example, with slight variations depending on the Warden's gender. In either case it consists of an elf and the Warden's cousin breaking into the Arl of Denerim's estate to rescue the kidnapped female wedding guests, and then the Warden teaming up with the aforementioned cousin to rescue a third cousin from the heart of the estate.
Archibald Ironfist is not a good man (for starters, his scheme to get the crown involves arranging for the murder of the Royal Seer, and then continuing to murder the successors until he can put the blame on his brother Roland). He also clearly feels a familial connection to Roland (note that he could just have arranged for his brother's murder to get the throne, but doesn't), culminating in Archibald risking his neck to save Roland from a horrible fate in Might and Magic VII.
In Shellshock 2, Nate's main motive throughout the game is not the orders he has been given or even a desire to stop The Virus. He just wants to find and help his brother Cal. In the end, he has to choose between a) saving Cal; and b) saving the villain so as to make him provide a cure. It's up to the player, but if players do choose to stick to this trope, the epilogue tells them that Cal dies a few weeks after his rescue anyway, while the zombie plague rages on.
In Lost Horizon, Lord Weston, governor of Hong Kong, takes this approach towards his missing son. He initially pretends otherwise, making a show out of downplaying his personal investment in the disappearance - he says he can't let the identity of the missing officer affect his duties. In reality, though, he has been secretly cooperating with the Nazis as a backup plan in case Fenton can't (or won't) rescue Richard. He eventually betrays Fenton to the Nazis for this reason.
This is a major theme of the Heaven's Feel route of Fate/stay night, as one of the plotlines explores Rin's conflicted feelings over her sister Sakura. On the one hand, she is prepared to take any measure to fight against evil, and as Sakura's shadow form gradually gains control, she becomes a major threat to the city. On the other hand, she cares about her sibling at heart, and she feels guilty over having had her sister taken from her as a child and subject to horrifying abuse at the hands of her foster family. She goes back and forth between these feelings over the course of the route, and only resolves it when, as she has a surefire killing shot on Sakura in the final battle, she realizes she loves her sister too much to harm her, and instead embraces her telling her how much she cares about her, all the while bleeding from Sakura's dagger which she was unable to avoid. This, however, gives Sakura the confidence to fight against her dark side again.
Zigzagged with Weiss Schnee, of RWBY. She dislikes the pressure her father puts on her to be perfect, and tries to avoid talking to him and her sister. But she doesn't tell her friends this, and always acts the dignified heiress in public- presumably because of this trope.
During the first volume, fans often argued whether Weiss was a proud snob acting like a nice person, or it was the other way around. Canon has not yet settled the debate, but it implies that both aspects of Weiss' personality are important to her.
Nale clearly believes that either this trope or Evil Is One Big Happy Family will protect him from any insult to Tarquin. He's wrong. After Nale gloats about killing his father's friend and confidante Malack, Tarquin gives him one chance to fall into line, and when he refuses said olive branch, Tarquin unceremoniously kills him.
Big Bob: "It'll make me a ton money, and what's good for me is good for all the Pataki's, if you catch my drift, Helga."
Helga: (to herself) "Alas, I ran again, torn between two forces. Arnold's foolish idealism... and my father's unbridled greed. And this time, I fear blood is thicker than water. Oh, curse the day I was born a Pataki!"
In one episode of Action League Now, The Flesh meets a couple who claim to be his long-lost parents; actually, they're a pair of crooks who want his Super Strength to rob a house. When the rest of the League comes to tell him this, Flesh is forced to choose between his friends or the parents he's always wanted. The Lemony Narrator asks at the Dramatic Cliffhanger, "Is action blood thicker than action water? And what exactly does that mean?" In the end, Flesh chooses his faux-parents, but by this time they're so fed up with his destructive bungling that they confess to the ruse anyway.
In The Legend of Korra, after a failed assassination attempt on Unalaq, Tonraq (his brother and the accused for leading the rebellion) says that even though he and his brother have their differences, he would never harm him in any way. Unalaq, however...doesn't feel the same way.
Adolf Hitler had a younger sister, Paula. After the war, she was interrogated by US intelligence officers, where she said this about Adolf: "The personal fate of my brother affected me very much. He was still my brother, no matter what happened. His end brought unspeakable sorrow to me, as his sister" Contrast to of his family. Several joined the U.S. military, and most changed their names. See the other wiki for more info.
Subverted in the Origin of the phrase. It meant that the blood of the battlefield is thicker then the water of the womb. So the person who you fought with should be treated better then your own family. Is it any surprise that it was the Ancient Spartans who came up with it?
It wasn't actually the Spartans. It came from originally a German proverb in the year 1180. The phrase really entered popular lexicon when American Commodore Josiah Tattnall uttered the phrase when he found his squadron accidentally engaged in the attack on Taku Forts when Anglo-French allies had attempted to breach a Chinese position. Tattnall made the split decision to aid the British (mostly by helping to evacuate the wounded and did not perform in a combat capacity) despite American neutrality. When superiors demanded to know what he had been thinking in violating America's strict neutrality, Tattnall simply uttered the phrase and thus it entered the common consciousness.
Invoked and defied in an apocryphal exchange between Czar Nicholas I and Napoleon III. It was customary for European monarchs to refer to each other as "brothers" (mon frere). When Napoleon III declared himself emperor, the Russian Czar addressed him as a "friend" (mon ami) rather than a "brother," to show his displeasure. Napoleon III, however, replied by declaring God gives us our brothers, we choose our friends.