History Main / SingleLineOfDescent

** You need not be too impressed if someone of European descent tells you that they are a descendant of Charlemagne. The only ones presently living in Europe who aren't would be non-Caucasians. Charlemagne sired over 18 children who would almost all have children of their own, and [[https://www.theguardian.com/science/commentisfree/2015/may/24/business-genetic-ancestry-charlemagne-adam-rutherford chances are nearly every European today has at least one of them as an ancestor]].

** You need not be too impressed if someone of European descent tells you that they are a descendant of Charlemagne. The only ones presently living in Europe who aren't would be non-Caucasians. Charlemagne sired over 18 children who would give rise to the major Caucasian groups in Europe, Anglo, Saxon, Frankish, Slavik, and Mediterranean.

* In ''Literature/ADiscoveryOfWitches'', Diana is the last Bishop and possibly the last Proctor, as we never hear about Stephen having any other family.

* ''WesternAnimation/TheLegendOfKorra'': Fire Lord Izumi and her son Iroh are both single children and the only descendants of Fire Lord Zuko. Albeit, this isn't as atrocious as other examples - Zuko is Izumi's father after all, not some ancestor from a thousand years ago. It's far from impossible for one person to have only one child who themselves have only one child. That being said, Zuko's sister presumably has no children and neither did his Uncle Iroh, so there remains the question as to what would happen to the Fire Nation monarchy if either Izumi or Iroh were to die.

* ''TabletopGame/{{Warhammer}}'''s Tyrion and Teclis have always been the only direct descendants of the first High Elf Phoenix King--Aenarion the Defender--from his first marriage to Astarielle over seven thousand years ago, and hence the direct inheritors of his bloodline and destiny. However, this trope was averted in the 7th edition High Elf army book (and the Tyrion and Teclis trilogy written afterwards) when it became clear that they're only the last surviving descendants, and the rest of Aenarion's heirs were systematically murdered by a Greater Daemon out for revenge against the bloodline of the elf who slew it. Given the extreme longevity and slow reproduction of elves, it helps that there have only been a handful of successive generations born during that time.
** The elves also maintain the tradition of the Everchild, an intentional attempt to preserve the female branch of the same bloodline. Unknown to pretty much everyone, the current one is also Tyrion's illegitimate daughter.
** Played straight during ''The End Times'' scenario when the character [[spoiler:Volkmar the Grim]] is revealed to be the last blood heir of Sigmar, who [[KingInTheMountain disappeared from human lands]] 2500 years earlier. Unlike with the elves, no slow generation time, ancient daemons with a grudge or bloodline breeding programme is involved, and Sigmar was known to have neither married nor sired children (The novels would reveal that Sigmar did have at least two illegitimate children, but they were never publicly acknowledged as such - Sigmar himself didn't know he was their father until they were adults), which is why The Empire has an ElectiveMonarchy in the first place.

* In ''VideoGame/TheElderScrollsIVOblivion'', the realm is protected from [[BigBad Mehrunes Dagon]] by Dragonfires, product of an ancient pact. At the time of the game, the last Septim Emperor is assassinated, laying the realm open to invasion by the Daedric forces. The main plotline of the game involves finding the hidden son of the last Septim and getting him the Phlebotinum he needs to start the Dragonfires again. The murdered Emperor ''had'' three other sons, all of whom were taken out in similarly nefarious assassinations shortly before the game begins (making the Blades the worst bodyguards in history). Martin survived because, as the bastard son of the Emperor, his existence was kept so secret that even ''he'' didn't know who he was. It does not address, however, the fact Uriel's sons were in their 50s and would have had their own heirs, who could well have had some of their own as well. Or Uriel's siblings and nephews. Or any female Septims.
** The backstory, however, averts this. The main Septim line already had had various winnowing events or outright going extinct. Mostly it just led to another branch becoming the main Septim line with the Elder Council's blessing and continuing the overall Septim line of Emperors (in one case, for example, a cousin supposed to be more closely related to Tiber Septim took over).

* In ''VideoGame/TheLostCrown'', William Ager was a villainous example. Unusual in that he died of tuberculosis with no heir to pass on the family secrets to, hence let down both Destiny and centuries of bloodthirsty tradition.

* Averted all over the place in ''VideoGame/BlazeUnion''. [[spoiler:Medoute]], the descendant of Gill the legendary dragonslayer, mentions repeatedly that she's from the secondary line. Characters also discuss that due to the Imperial bloodline being so diluted and spread throughout the people, it's not unusual for children qualifying as Brongaa's descendants to be born in all walks of life; the interesting thing about Gulcasa is that he's the first pureblood to be born in centuries.
* Also averted in ''VideoGame/TalesOfSymphonia'', where the family of the Chosen is huge, has many branches, and is scattered all over the world so that if something happens to one branch, the bloodline will still exist.
* In ''VideoGame/DragonQuestVIII'', the BigBad is tracking down the descendants of the Seven Sages who originally [[SealedEvilInACan sealed him away]], as their deaths are the only way to release his original body. The game establishes that only one descendant in each most recent generation is the heir (as Jessica's brother Alistair held the bloodline whereas Jessica just received magical strength), with an odd exception in the case of Marta; while she had a son, he decided to practice medicine in a nearby town, figuring his skills would be put to better use there, and forfeited his status as an heir in the process (which managed to throw the BigBad off for a bit).
* Inverted in ''VideoGame/FableIII'', only the ''youngest'' of the Hero of Bowerstone's two children gets any Hero powers.
* In ''[[VideoGame/RiseOfTheKasai Mark of Kri]]'', the marks are passed down through the firstborn descendants of six separate families, one mark per family, with at least two of the families having willingly died out to prevent their marks from being passed down any further. In an interesting turn of events, however, it is TheHero's ''younger'' sister who bears the mark, even though he is the firstborn, though the second game hints that they may not actually be related.

** In ''VideoGame/TheLegendOfZeldaALinkToThePast'' and ''VideoGame/TheLegendOfZeldaFourSwordsAdventures'', Link is a descendant of ancient heroes. Made more explicit in ''[[VideoGame/TheLegendOfZeldaTwilightPrincess Twilight Princess]]'', where that game's Link is directly descended from [[VideoGame/TheLegendOfZeldaOcarinaOfTime The Hero of Time.]]

* Subverted in ''VideoGame/DragonQuestV'', where whichever of the two/three (depending on the version) available brides the main characters marries becomes the mother of the hero destined to put on the Zenithian gear and destroy the BigBad. The children themselves all have the same personality regardless of their mother [[spoiler:not too surprising considering they only met their mother and father almost a decade later and after de-statueing them]], only taking her hair color (blond, blue or black).
* In ''VideoGame/DragaliaLost'', the player character Euden's dragonblood is shared with his siblings. However, the will of their ancestor, Alberius, is only truly passed to him, and Euden is seen as the direct descendant. [[spoiler:His siblings end up joining forces with the BigBad, Morsayati.]]

* ''WesternAnimation/TheLegendOfKorra'': Fire Lord Izumi and her son Iroh are both single children and the only descendants of Fire Lord Zuko.

* ''Franchise/BuffyTheVampireSlayer'': In ''The Gatekeeper Trilogy'', there has only ever been one heir to the Regnier family GateGuardian job at a time since Richard became the Gatekeeper, making Jacques the only Regneir left to continue the line. Although Richard's wife was murdered soon after the birth of their son and Jean-Marc's wife went insane and committed suicide, it can seem odd that Henri and Antoinette only ever had one child.

* ''ComicBook/DisneyDucksComicUniverse'': In ''ComicBook/TheLifeAndTimesOfScroogeMcDuck'' Creator/DonRosa, Scrooge [=McDuck=] is often lauded as the last of the once great Clan [=McDuck=], whose lineage contains knights, merchants, magnates, Templars, and all manner of greatness. This despite the fact that he is only the last MALE member of the Clan, and his two sisters apparently [[LineageComesFromTheFather not counting]], one of whom had children and grandchildren of her own, these of course being his nephew WesternAnimation/DonaldDuck and his nephews.

* ''ComicBook/DisneyDucksComicUniverse'': In ComicBook/TheLifeAndTimesOfScroogeMcDuck by Creator/DonRosa, Scrooge [=McDuck=] is often lauded as the last of the once great Clan [=McDuck=], whose lineage contains knights, merchants, magnates, Templars, and all manner of greatness. This despite the fact that he is only the last MALE member of the Clan, and his two sisters apparently not counting, one of whom had children and grandchildren of her own, these of course being his nephew WesternAnimation/DonaldDuck and his nephews.

* ''ComicBook/DisneyDucksComicUniverse'': Scrooge [=McDuck=] is often lauded as the last of the once great Clan [=McDuck=], whose lineage contains knights, merchants, magnates, Templars, and all manner of greatness. This despite the fact that he is only the last MALE member of the Clan, and his two sisters apparently not counting, one of whom had children and grandchildren of her own, these of course being his nephew WesternAnimation/DonaldDuck and his nephews.