Royal Blood

"The hands of the king are the hands of a healer, and so shall the rightful king be known."

- Ioreth, Wise Woman of Gondor, The Return of the King

Royal Blood! It's real, it's significant, and only the person who's really got it is suitable for the throne. Obviously required for the Rightful King Returns. In Fantasy, may actually endow the person with magical powers, giving additional meaning to the term MacGuffin Girl, or even be required by the land (and, unfortunately, making it useful in Blood Magic). Features even in SF for a Feudal Future. And when it comes to being Offered the Crown, Royal Blood may encourage them to choose you.

Useful rule for at least curbing the excesses of a Succession Crisis. On the other hand, the Arranged Marriages to preserve it may lead to Royally Screwed Up Families, especially since the parents, and grandparents, etc. of the bride and bridegroom were also, likely Kissing Cousins. (The Arranged Marriage is very common, although fictional royalty find it remarkably easy to throw off the arrangements, marry for love, and face no repercussions. Like, say, war in the event of a dynastic marriage.) Heir Club for Men and I Want Grandkids are common.

In combat, No One Gets Left Behind applies with particular force to those of Royal Blood. Even if they are dead, the soldiers often go to great efforts to recover the body. Leaving aside issues of honor and loyalty, there is also the grim necessity of being able to establish that this person died, so that succession can be more or less orderly (Especially since this often occurs in time of crisis).

Idealistic stories on the Sliding Scale of Idealism Versus Cynicism generally have the rightful king also be the better ruler. More cynical stories split them up, and then even Lawful Good characters may support the worse ruler because the one who would be a Reasonable Authority Figure would create a dangerous precedent in ignoring the laws of succession. Royal Blood may require your putting up with Royal Brats, The Evil Prince and The Caligula -- all the time, if it's In the Blood.

May lead to the Man in The Iron Mask.

Will likely be inherent in a Princess Classic and Prince Charming. Obviously common in the Standard Royal Court or Deadly Decadent Court.

Will often appear with Ermine Cape Effect and Requisite Royal Regalia, where royalty uses visible clothing to show off their status -- all the time. Conversely, Modest Royalty may appear humbly dressed all the time. (In Real Life, royalty will usually dress practically, and in special circumstances, dress to impress.)

Compare Blue Blood, Idle Rich.

Anime and Manga

 * Something similar to the Stargate take occurs in Mai-Otome, where the members of the Windbloom royal family have the inherited ability to activate Lost Technology.
 * Sheeta  in Castle in The Sky
 * Two members of the Royal House of Roshtaria working in concert are the only ones who can control the Eye of God.
 * Fruits Basket: Sohma Ayame's elaborate explanation of why he had to have long hair invoked this trope.
 * One Piece has yet to show how much it is buying into this trope, but the Marines certainly believe in it. The royalty they are tracking is . And then there are the Celestial Dragons, . Their royal blood affords them immense wealth and political power which they are more than willing to abuse for the sake of their own amusement.
 * The various royal lines of the Ancient Belka kings in Magical Girl Lyrical Nanoha come with various powers that allow them to become Persons of Mass Destruction. The reason behind this isn't as idealistic as most examples though. During the Ancient Belka War, the different factions delved deeply into genetic engineering to seek an upper hand over everyone else, and their kings greatly modified themselves to not only gain these powers power, but to force these powers onto their descendants as well.
 * In Mahou Sensei Negima,  have Royal Blood, but in this case there's a good reason that this is important, as the person who started the royal bloodline is heavily implied to be the mage that created the Magic World. Konoka is also of Royal Blood, from a different family. This is a key plot point in the Kyoto arc and ignored after that.
 * The whole Royal Bloodline thing is a plot point of sorts in the initial Tenchi Muyo OVA series. It's mostly used to confirm that Tenchi is actually related to the then-thought long lost Prince Yosho, and thus a member of the Juraian Royal Family. It doesn't sit well with Emperor Azusa.

Comic Books

 * In the X Wing Series comics, the Boisterous Bruiser of the group, [[media:Plourr.jpg|Plourr Illo]], was revealed to be the last of the Eiatu royal line, her parents and sisters having been killed by other nobles in a revolution. A noble who she initially believes to have been in on that gets her to head back to her homeworld, Rogue Squadron in tow, to try and take over. Most of the nobility is happy enough with that, especially since there's another revolution going on, this one led by someone who claims to be another survivor. Her brother.
 * In the Hellboy comics, was recently revealed to be  . Among other things, this means that
 * In the Sonic the Hedgehog series, the Acorn bloodline plays a number of important parts in the story, though it was mostly so Sally to use a powerful artifact of her family's. An interesting plot point was made, though, when Sally's brother Elias stepped up to the throne - their mother, Alicia warned that his wife's child could never be a princess because he didn't sire her. He's more than happy to make sure she never takes up the throne.

Fairy Tales

 * All the Prince Charmings and princess equivalents that heroines and heroes marry at the end of story -- too many to list. The heroes and heroines have more variation
 * In The False Prince And The True, a young man is put on trial for his life because he struck the prince. He saves himself by revealing that the purported prince was a quarryman's son, and he is the king's son by a secret marriage.
 * In The Lute Player, the couple are the king and queen.
 * In Maid Maleen, she is a princess.
 * In The Six Swans, both the heroine and her six brothers.
 * In Costanza / Costanzo, Costanza nobly rejects the notion of marrying below her Royal Blood.
 * In The Bee and the Orange Tree, the girl living with the ogres who saves the prince is herself a princess -- and the prince's own cousin.
 * In Finette Cedron, the sisters are abandoned by their parents in the woods for reasons of poverty -- even though they are king and queen.
 * In Rushen Coatie, the heroine is a princess.
 * In Princess Belle-Etoile, the story requires that the heroine be in poverty in the opening, so she's the daughter of a princess in reduced circumstances.

Film

 * The Court Jester.
 * In Atlantis the Lost Empire, her royal blood is the reason Kida is transformed into a serene goddess-like figure upon contact with the main crystal while Rourke is... well... not so lucky. Unfortunately, Disney actually did not realize this, since they accepted "any other" and excluded "some of royal blood", despite considering Rourke as an official Disney Villain.
 * Stardust has their royalty reappear as ghosts if they die before the next king is crowned (which they likely will, because it's a family tradition to bump the male siblings off, and the last man standing gets the crown). Unfortunately, their ghosts look the same way they did at their time of death, . They also are apparently literal Blue Bloods. . They're from Another Dimension.

Legend

 * King Arthur, who could only pull the sword from the stone because he was secretly the son of Uther Pendragon.

Literature
"DUKE. Why, the Professor here who performs before the King [puts down the programmes]--you see it on the caravans, you know--performs before the King almost every night, I suppose...
 * In Lord of the Rings, the royal line of Numenor/Arnor/Gondor and thusly Aragorn descend from various elven royal families and human royal families of the First Age, and a divine spirit as the first of several cross-race-marriages. The people of Gondor have the saying of the opening quote, that royal blood gives him healing powers.
 * Probably based on the real-life myth that kings could heal scrofula (a skin disease) by Laying On Hands. A lot of French kings actually spent quite a lot of time doing this, for instance. It was part of the job.
 * It was officially restricted to scrofula from 'illness' pretty late in the Middle Ages, to cut down the annoyance and chance of contagion and number of people annoyed about it not working. Right through the seventeenth century, though, people kept coming with things like leprosy.
 * JRR Tolkien was also influenced by the New Testament, where Jesus is the rightful King of Israel and spends much of his ministry healing people. Also, in Anglo-Saxon, Christ or Messiah is translated into something very close to modern English's word "Healer".
 * And not just "various" royal families. Tolkien took this trope to extremes: via a pretty complicated family tree, Aragorn's son Eldarion is the ultimate in Royal Blood: the High King of all elves and men in the entire world.
 * In The Prisoner of Zenda, they are willing to try the imposture, because he is himself illegitimately descended from a Ruritanian king. The fact that the impostor looks exactly like the king helps...
 * Subverted in Terry Pratchett's Wyrd Sisters; they end up choosing between two half-brothers, but they are not the king's illegitimate and legitimate sons, but his court jester's legitimate and illegitimate sons. The king's ghost (who doesn't know any of this) is still happy.
 * It is also hinted several times that part of the reason that Carrot is so liked by EVERYONE is because of his royal lineage. But it's also suggested (including by Carrot himself), that even a good king is a bad idea, so he keeps quiet about it.
 * In a typical Discworld subversion, Sam Vimes makes the offhand comment that drawing a sword from a stone wasn't very special; you could hire a dwarf to hide inside and hold onto it with tongs until the "right guy" came along. Being able to stick a sword into solid rock... well. That's much more interesting. Carrot demonstrates such an ability, without really noticing or caring at the time.
 * True Troll Kings are rather hard to miss, since Discworld trolls are made of Metamorphological rock, and the kings are made of Diamond.
 * Troll Kings are actually a subversion of Royal Blood. There is no royal blood silicate line, as a Troll King arises among trolls only in times of duress.
 * Any troll with a diamond composition could make itself a king (or, presumably, a queen) if it wanted, because they're all but indestructible and much smarter than the rest.
 * According to Mr Shine, any troll with a diamond composition becomes king whether they want or not, since unlike Carrot, hiding isn't an option.
 * from A Song of Ice and Fire are currently trying . They need a royal blood sacrifice to do so, so other characters are actively hiding children that could even remotely be considered "kings blood"..
 * Being a member of the Royal House of Amber makes one practically superhuman, with great strength, impressive healing, the Trumps, the ability to walk between worlds... Being so powerful means their only real competitors are other members of the Royal Family. Being a scheming lot, this leads very quickly to a Gambit Pileup...
 * In Garth Nix's Old Kingdom series, several bloodlines including the royal one were invested with a lot of the power of the makers of the Great Charter. Prior to the events of Sabriel, the Old Kingdom had been in steady decline since the apparent loss of the royal bloodline protecting it.
 * In L Frank Baum's second Oz book, The Marvelous Land of Oz, Glinda tells the Scarecrow of Princess Ozma, and everyone immediately agrees that she is the only possible heir, being the last king's daughter.
 * There was a Choose Your Own Adventure book, Black Vein Prophecy where you are a member of a family of Royal Wizards.
 * In Randall Garrett's Lord Darcy stories, the throne of England combined with that of the Holy Roman Emperor. As a consequence, it is elective, but only among the Plantagenet line. At one point, we see the king's brother thinking that his nephews are more likely candidates but he is a possible one.
 * In John Barnes's One for The Morning Glory, Prince Amatus is asked to cure the sick because a prince's touch can do that. Works, too.
 * Jim Butcher's Codex Alera has increasing amounts of magical power amongst the nobility with the First Lord (i.e. the King) being the most powerful.
 * Though this is implied to be as much Asskicking Equals Authority as it is Royal Blood- more powerful crafters automatically get more respect, and therefore get high titles, and therefore pass both powers and titles on to their children.
 * An example of this being subverted is Isana. She's just a steadholder, and her power is apparently limited. However, in Captain's Fury and later Princeps' Fury she realizes that the concept of power being limited to station is so heavily ingrained into her - and by extension, the rest of Alera's - consciousness that it was effectively blocking her full potential.
 * In Dorothy L Sayers' Lord Peter Wimsey novel Have His Carcase, the murder victim was convinced he had Royal Blood. . His blood ended up being an important clue.
 * In Patricia a McKillip's Riddle of the Stars trilogy, kings have a mystical bond, called "land-law" that allows them to sense their own kingdoms.
 * Poul Anderson's A Midsummer Tempest takes place in an alternate English Civil War. Prince Rupert is the main character..
 * In CS Lewis's The Magicians Nephew, Jadis treats with contempt the notion that Uncle Andrew could be anything but a king: Royal Blood and magic go together. Who ever heard of commoners being magicians? Whether this is Authority Equals Asskicking or -- in light of her ruthless use of magic for power -- Asskicking Equals Authority is not clear, but she certainly treats it as the former.
 * In Fiona Patton's Tales of the Branion Realm, the royal line is possessed by a fire god -- they all have fiery eyes, the fire growing brighter as one gets closer to the throne. This neatly cuts out the problem of illegitimacy, but one king is remembered as "The Bastard", since his foreign mother seduced the king in order to end a war by having her son inherit.
 * In Christopher Stasheff's Her Majesty's Wizard, the Queen is truly infallible -- whatever she says essentially becomes true. When she confers virtues (such as bravery) on a knight, the knight visibly gains those virtues. It only works on issues of policy or governance, being tied more into Divine Right. When the issues become personal, all bets are off.
 * Commonplace in Edgar Rice Burroughs's works, especially the John Carter of Mars ones. Though some don't know it.
 * In The Chessman Of Mars, Corpals "that by commanding the spirits of the wicked dead gains evil mastery over the living" are said to be killable only by those of Royal Blood. And the weak and cowardly king can not be deposed for a noble and brave nobleman; fortunately, he also has a brave and popular son whom he hasn't killed yet.
 * In the Dune series, the Imperial bloodline (and that of several noble families which are closely related to the Imperial family) are secretly bred by the Bene Gesserit for Psychic Powers. During and after the rule of Leto II, descendants of the Imperial/Atreides line develop these and other useful "talents", including protection from prescience that makes them vital to humanity's survival.
 * In P.C. Hodgell's Chronicles of the Kencyrath, a magical significance attaches to being of the house of Knorth, the Highlords' house. Breeding programs long ago concentrate certain Shanir (magical) abilities in certain Houses. Historically, most breeding pairings were between close relatives, concentrating the bloodline, the talents, and the negative traits that come along with them.
 * Played very straight in Katherine Kurtz's Deryni books. Faced with a tyrannical king Camber's family track down the last descendant of the previous royal house (which was overthrown three generations ago)... and when they find him minding his own business as a celibate monk under a vow of silence, they kidnap him in the dark of night, hold him prisoner for nearly a year, force him to marry at swordpoint, and use mental and magical coercion to make him into a king. The resulting three centuries of persecution for the Deryni might be viewed as karma.
 * In the second book of the Camber trilogy Joram points out to his father that he (Camber) could have made himself king with fewer problems then Cinhil Haldane is having. Camber argues that that would have made him no better then the Deryni Festils as he has no royal blood and no legal right to the throne of Gwynedd.
 * In Jim Butcher's Dresden Files novels, appears to be standard for Knights of the Cross.
 * Though it seems that Knights of the Cross are more along the lines of King Under the Oak Tree/Fisher King type of royalty as epitomized by Captain Carrot from Discworld. More king of the land than king of its people.
 * Royal Blood is noted as helping one attain status as a Knight of the Cross, but is far from necessary. After all, both  become temporary Knights during Changes, and there's no indication that either of them have royalty in their ancestry - just righteous amounts of love and faith, respectively.
 * Come on, Murphy is Irish and as everybody knows all Irish are descended from kings!
 * may technically count, since the was supposedly the progenitor of all.
 * In the Wars of Light and Shadow series by Janny Wurts, royal blood is important for more than symbolic reasons -- the founders of the five royal dynasties were all given a certain trait (compassion, justice, etc) which would be inherited by their successors. Plus, the charters under which the monarchies were established were an important part of the deal which gave humanity permission to settle in its current home. The fact that the monarchies were all overthrown a few centuries before the start of the story is a significant plot point.
 * Invoked in GK Chesterton's Magic
 * Invoked in GK Chesterton's Magic

CONJURER. [Smiling.] I sometimes let his Majesty have an evening off. And turn my attention, of course, to the very highest nobility."

"To avoid the possible chance of hereditary diseases or such things, we have abandoned hereditary monarchy. The King of England is chosen like a juryman upon an official rotation list."
 * In The Napoleon of Notting Hill, this has been abandoned.

""You came by the Royal Road, sweet one. Only those of royal blood can travel along it: but you've been royal ever since I was made King of Elfland that's nearly a month ago. They sent two ambassadors, to make sure that their invitation to me, to be their new King, should reach me. One was a Prince; so he was able to come by the Royal Road, and to come invisibly to all but me: the other was a Baron; so he had to come by the common road, and I dare say he hasn't even arrived yet."
 * In Ursula K Le Guin's A Wizard of Earthsea, Ged found an old man and woman stranded on an island. In The Tombs of Atuan, Tenar explains that they were a prince and princess, the last of their family, whom the God Emperor had abandoned at sea as infants as he feared to kill those of Royal Blood. They don't get a happy ending.
 * In Wen Spencer's Endless Blue, Mikhail's family. Though they resorted to cloning rather than the usual.
 * In Lewis Carroll's Sylvie and Bruno.

"“By the Cross,” she said, “I cannot but think that ye are come of noble blood. By your courtesy I know it, and by your great fairness.”"
 * While there aren't any kings on Pern, the bloodline that ruled Ruatha Hold was known to produce many heirs with enhanced telepathic talents.
 * In the Chivalric Romance Roswall and Lillian, Roswall has been reduced to poverty and the king's service, but the princess Lillian, even when told his father was of low degree, correctly discerns his Royal Blood.

"''"But for all your stupidity, you are a woman fair to look upon. It is my whim to keep you for my slave."
 * In Robert E Howard's Conan the Barbarian story "The People of the Black Circle", Yasmina is very proud of hers. It makes the Break the Haughty all the more humiliating.

The daughter of a thousand proud emperors gasped with shame and fury at the word.

"You dare not!"

His mocking laughter cut her like a whip across her naked shoulders.''"


 * In L. Jagi Lamplighter's Prospero In Hell, Queen Agave of Thebes. It startles Miranda to realize this about her brother's cook.
 * In Robert E Howard's Kull/Bran Mak Morn story "Kings of the Night", one tribe demands to be led only by a king, and one of their own blood.
 * In Josepha Sherman's The Shining Falcon, one royal family is also magical; you have to be able to turn into a bird to prove you are royal.
 * In Adrian Tchaikovsky's Shadows of the Apt, Royal Blood is good for Blood Magic.
 * In Stephen Hunt's The Court Of The Air and The Rise of the Iron Moon, a very bad thing to have: Jackals keeps around royals to be abused, and deliberately breeds them.
 * In John C Wright's Count to a Trillion, the princess observes that despite this, she is a commoner, not having an actual title.
 * Done every which way in Lloyd Alexander's Chronicles of Prydain. Most notably, there's the matter of the sword Dyrnwyn, which bears an inscription explaining that gets quoted early in the series as Draw Dyrnwyn, only thou of royal blood... The heroes give the blade to their friend Prince Gwydion, who is able to use it because he does indeed fit the description - except that the sword's runes have been mistranslated. It's actually Draw Dyrnwyn, only thou of noble worth... While that still applies to Gwydion, it also opens the door for someone else to use the sword later.

Live Action TV

 * One episode of Stargate Atlantis is based on the premise that only those with the Ancient Technology Activation gene can be royalty, because this gene is required to activate the technology required to protect the planet.
 * Babylon Five: the Triluminaries are attuned to genetic inheritance of Valen.

Tabletop Games

 * In the 3E Ravenloft products, Camille Dilisnya claimed legal ownership of the new-made domain of Borca after passing arcane tests to confirm the validity of her Dilisnya bloodline.
 * In Exalted, the nobility of The Realm are all related to the Scarlet Empress (her descendants, or in-laws thereof). Since their Superpowerful Genetics means many of them are Terrestrial Exalted (elementally-empowered Supersoldiers), the Royal Blood really does have powers.
 * In the Birthright campaign setting for Advanced Dungeons & Dragons, characters with royal blood have a divine power known as Regency.
 * Played With in Traveller . The Imperium is held together by a Feudal Future. However the only advantage claimed for aristocratic blood is that something has to hold the Imperium together, it is nice to have people around who were trained to run the Imperium in their nursery's even if some of them turn out to be Upper Class Twits, and that there has to be a way of choosing someone to be the boss and with trillions of people that is kind of a bother. And besides, Ermine Cape Effect is cool.

Theater

 * William Shakespeare used it all the time.
 * Some critics have attributed the sterling character of the princes in Cymbeline and the princess in The Winters Tale to a belief that royal blood would show up in their character, but, on the other hand, in both those plays the older generation, just as royal, is distinctly less sterling.
 * In Macbeth, Malcom and MacDuff discuss how Edward is (off-stage) touching for the king's evil. (See comments under The Lord of the Rings.)
 * In Prometheus Bound, Prometheus tells Io that a descendant of hers will bear "A royal race in Argos."
 * Gilbert and Sullivan use it in Princess Ida, but subvert it hard and then play it straight in The Gondoliers. One of two Venetian Gondoliers is believed to be the heir to the vacant throne of the Mediterranean island kingdom of Barataria. Until it can be determined which is the actual king, they reign jointly -- but being Republicans who "hold kings in detestation" they do all of the work around the palace, allowing their servants lives of total leisure. Then played straight.

Traditional Games

 * King's Blood is essentially UNO played with British-style royalty. So naturally, a perfect example of this trope.

Video Games
"Gafgarion: Even Princesses can die for getting in the way. That's what 'royal blood' is all about!"
 * In The Elder Scrolls IV: Oblivion, only one of the Dragon's Blood can wear the mystical Amulet of Kings, or so the stories say. The Big Bad of the game is ALSO able to wear the Amulet, on account of his descent from an older, discredited royal blood line.
 * In most of the Fire Emblem series, you have one or more 'Lord' units. Invariably of Royal (or at least highly noble) Descend, they also tend to have higher stats than any unit you haven't deliberately twinked out. (...at least most of the time...Yes, I'm talking to you, Leaf and Eliwood!) Not to mention being heroic, beautiful, inspirational, and so on and so forth...
 * Sometimes in the games, royal blood also grants powers that make them worth using over another unit. Other than plot roles such as Louise's relation to the Queen of Bern getting the characters an audience with her or the princess of a foreign land aiding the army, there are some certain combat privileges to being royal. A usual example are weapons only those of royal blood can use. (Namely weapons like the Rapier, Hector's Wolf Beil, Leaf's Light sword, etc) However, when the royal unit is a normal class unit, they may still have some specific weapons only they or another royal can use.
 * In the first game, Marth's sister Elice was kept alive because she could use the Aum staff, which can only be used by a princess.
 * It's a big part of the canon in the fourth game, in which not only are there just Sigurd and Celice, who are lords, but various other members of the royalty or descendants of the crusaders. This also ties into the Big Bad Julius's blood, as well as the Game Breaker Julia's.
 * Some normal units actually may be royalty but they're practically just regular units. Some characters also have a plot twist about them when they suddenly reveal themselves to be of royal blood, or are found to be royalty.
 * This is the very reason that Estelle is able to  In Tales of Vesperia. Estelle's power is also.
 * And in Tales of the Abyss, a prophesy speaks of a Chosen One who will be "a boy of Royal Blood''.
 * In Der Langrisser, the only ones who can wield the titular Langrisser are the Descendants of Light, of the blood of Lushiris. These individuals also tend to be highly powerful fighters on the field.
 * Mocked in Final Fantasy Tactics.


 * In The Legend of Zelda, the females of the royal family are endowed with Psychic Powers, often the Triforce of Wisdom and the name "Zelda". Also, even without the Triforce, said Psychic Powers cause her to be an almost endless source of magical energy. All of this combined causes the Princesses Zelda to be very popular targets of supernatural kidnappers. Therefore, it sucks to be royal and female in Hyrule. No wonder that the Hyrulean Princesses tend to develop a tomboyish side.
 * Etrian Odyssey III: The Drowned City has Princesses and Princes, a Class centered around their Royal Lineage.
 * Fable: In the first installment into this series it's implied that the main character descends from an ancient royal bloodline and it's outright stated a sacrefice of said blood is needed to unlock the full potential of the Sword of Aeons. The other installments in the series also imply a sort of inborn heroic power behind this bloodline as it is essentially the family each player protagonist descends from and the major reason your character can pull off most of their many heroic and death defying feats...like falling out a window some 10-20 stories up.
 * Dragon Age: Origins, the Orzammar Succession Crisis, puts you in the dilemma of choosing between a radical Royal Blood heir and a more reasonable mere-noble successor named in the late king's last will. The twist is that . Also, after the landsmeet, you have to decide between making king, thus preserving the Royal Blood, or confirming the Iron Lady Anora (the widow of King Cailan) as queen. Thankfully, there is a third option here: persuade the two of them to marry so they can have their cake and eat it, too. Rhere is even a fourth option, if your character is a human of noble blood... have one of them marry you! You just need to be suave enough.
 * It's the reason that the Player Character's sister is killed in the PC game Shades of Death: Royal Blood - she's a countess and her Royal Blood is needed to revive the king of vampires.
 * Flora, in the Professor Layton games, is the daughter of a baron. Her genealogical connection to the royal family forms part of the plot of the bonus game Professor Layton's London Life.

Web Comics

 * In No Rest for The Wicked, November can detect royal blood. She tells Perrault that the Marquis has no royal or even noble blood (if you've read "Puss In Boots", you know she's right there) and later deduces that Clare is royal, but only by marriage (if you're read "The Girl Without Hands", you know she's right there, too.) On the other hand, this doesn't seem a common ability; the Marquis is widely accepted, and November's ragged appearance convinces all and sundry that she's no princess.
 * Drow Tales: Faen's empathic abilities.
 * Naturally it shows up in Arthur King of Time and Space. In the space arc, for instance, the starship Excalibur activates in response to scanning Arthur's DNA.
 * Girl Genius: The Heterodyne family! Also shows up in the lesser sparks and the royal families of Europa -- Baron Wulfenbach uses it to keep the peace by holding hostage members of prominent families.
 * This is part of the conflict in Erfworld; as with the Fire Emblem example above, Royal units tend to have higher starting stats. This is the only real difference between Royals and "normals"- Stanley was made an heir by King Saline IV, which Ansom takes as a grave mistake.
 * Impure Blood Going somewhere, princess?
 * In Roza, the horse is a prince.
 * In Strays it's Prince Holland.
 * In The Beast Legion, the prophecy explains that only one from the royal bloodline will be the one to stare Evil in face & fight for hope. Xeus is a direct descendant of the bloodline of Minos Kings of Lithopa.
 * In Thistil Mistil Kistil, Loki assumed it
 * In Nip and Tuck, used as a rebuttal.

Real Life

 * From the beginning of The Middle Ages to the end of the Renaissance, monarchs in England and France were thought to be capable of healing citizens (which is likely where Tolkien got his idea of Aragorn being a healer) of scrofula (known as the "King's Evil" as it was thought only the monarch could cure it) simply by laying their hands on the person, murmuring, "God grant you good health," and giving them a coin. This ended in England after Queen Anne failed to cure the future Dr. Samuel Johnson (of Boswellian fame) and her successor George I condemned the practice as "too Catholic," and was ended by Louis XV in France, although a brief resurrection in 1825 was widely ridiculed.
 * King Charles II of England notoriously did not want to touch for the King's Evil, but was persuaded to do so as a sign of the continuity of the monarchy after the Restoration. He is said to have muttered to a scrofulous victim brought to him, "God grant you good health -- and better sense."
 * It was also played more or less straight without the superstitious element, as the various thrones in Europe were frequently occupied by rulers of foreign lineage, which all passed without comment because they were still of Royal Blood -- the different royal/noble houses of Europe were occasionally treated like one big intermarrying family.
 * In most of the kingdoms of southern Nigeria (especially the iconic ones like Benin and Oyo), local religious beliefs hold that the gods, ancestors and other spirits upholding the kingdom have a contract of sorts with the royal family. Exercise of this franchise allows the king to perform special ceremonies to avert disaster or solve crises. For instance in 2010, amid increasing incidences of armed robbery around the city of Benin, the Oba of Benin conducted a new ritual intended to cleanse the town and place a curse on all robbers. So revered is the Oba and his office that (according to police), crime rates dropped acutely in the following monthly reports.
 * People with the surname Fitzroy (or an ancestor with that surname) are typically illegitimate descendants of a (British or English) king. Other Fitzes have been used for the illegitimate children of royalty, most notably FitzClarence, the illegitimate children of King William IV of the United Kingdom (the children were all born while he was still the Duke of Clarence); FitzCharles, for some of the illegitimate children of Charles II (others used Fitzroy, the name of their mother's husband, or in one case, the odd choice of "Tudor"); and Fitzjames, the illegitimate children of James II. Most people whose name is "Fitzsomething" aren't royal bastards, though.
 * Arguably, the entire human race can claim at least some strain of royal blood. It's been stated that most everyone in the Western world is descended from Charlemagne. This is because with every generation going backwards through time, your number of ancestors doubles - you have two parents, four grandparents, eight great-grandparents, etc. - and the population of the world has been such that it would be almost impossible for an individual to not claim at least one royal ancestor. The concept is explained in detail here.