History Main / SingleLineOfDescent

* Subverted trope in TheBible, in that Jesus needs both father ''and'' mother to be both descendants of the entire Davidic dynasty. Through his mother he gets biological descent, and through his adoptive father who has direct male descent he becomes legal heir. Not to mention that Jesus has several brothers (and there's a possibility that his cousins on his mothers side may also have the same descent).

* In the ''VideoGame/{{Castlevania}}'' series, only the Belmont family has the power to vanquish {{Dracula}} when he rises every 100 years (though there have been many exceptions). Each time he rises, there are only one or two Belmonts around to do the job.

** Exception: The plot of the cell phone game ''VideoGame/{{Castlevania}}: Order of Shadows'' involves three Belmont siblings, two of them women. But only the guy gets to take on Dracula, and the game isn't considered canon anyway.
*** It is stated that the villagers in ''Castlevania: Order of Ecclesia'' are of the Belmont lineage, but don't have their last name.

* ''DeltoraQuest'' establishes that by tradition, the ruler of Deltora has only one child, meaning during the time of ''Deltora Shadowlands'', Adin (the first king) has only one heir. If that heir dies childless, the power of the Belt will be lost forever. [[spoiler:It's eventually subverted. Lampshaded/Invoked Guess why the tradition got started.]]

* Not so in Creator/JRRTolkien's ''TheLordOfTheRings'', where multiple lines and descendants exist. An example are the kingdoms of Arnor and Gondor, respectively founded by Elendil and his sons, who are descended from a sideline branch of the Númenórean royal family: in both cases there are various people (both properly royal and more mundane ones) appearing and mentioned as descending from the same ancestor as the "main descendant(s)" of that line. Gondor even eventually [[SuccessionCrisis endured a civil war over the question of inheritance, had problems with multiple potential claimants, and eventually no viable successor could be found who would have pleased everyone, resulting in the Stewards taking over]]. When the Gondorians first had trouble finding a royal successor, the Arnorian line and kingdom was still fully intact, and the Arnorian king tried to take over (on account of both dynasties being descended from Elendil and being married to the last Gondorian king's daughter) but was rejected. His descendant Aragorn would later succeed where he had failed.

* In the movie of ''TheDaVinciCode'', there is only one surviving member of [[spoiler: Jesus]]'s bloodline. (In the book, though, the corresponding character has a sibling, and it's stated that they aren't the ''only'' line of descent, just the most reinforced and "qualified". That apparently wasn't dramatic enough for the movie, though.)

* Carrot Ironfounderson is apparently the last living descendant of the {{Discworld}}'s ancient Kings of Ankh. This has been supported by evidence uncovered by Edward d'Eath in ''Discworld/MenAtArms'', and by [[spoiler: Dragon King of Arms']] inability to find a better alternate successor than Nobby Nobbs in ''Discworld/FeetOfClay''. In Carrot's case, the lack of other heirs is at least implied to have been engineered, as he was the SoleSurvivor of an attack on a caravan in which the long-lost royal sword had been carefully hidden.

* In ''Literature/HarryPotter'' [[BigBad Voldemort]] is the last descendant of Salazar Slytherin, one of the four founders of [[WizardingSchool Hogwarts]]. It is {{Justified|Trope}} by explaining that Slytherin's descendants became so obsessed with keeping the line "pure" that they repeatedly married within the family.

* Averted all over the place in ''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.

* ''JoJosBizarreAdventure'' starts off this way, but beginning around the Stardust Crusaders arc there are multiple Jojos running around at once. And then the concept of who's descended from whom starts to get tricky...

* Carrot Ironfounderson is apparently the last living descendant of the {{Discworld}}'s ancient Kings of Ankh, as confirmed by evidence uncovered by Edward d'Eath in ''Discworld/MenAtArms'' and by [[spoiler: Dragon King of Arms']] inability to find a better alternate successor than Nobby Nobbs in ''Discworld/FeetOfClay''. In Carrot's case, the lack of other heirs is at least implied to have been engineered, as he was the SoleSurvivor of an attack on a caravan in which the long-lost royal sword had been carefully hidden.

* In the ''Series/StarTrekTheNextGeneration'' episode "Sub Rosa", we learn that a "ghost" named Ronin has been bedding Dr. Crusher's female ancestors for centuries, moving from mother to daughter, and is now moving onto Crusher following the death of her grandmother Felisa Howard. The logical flaws start with the fact that all her female ancestors were apparently named "Howard", indicating that Crusher is the first woman in her family to lose her maiden name, despite her living in the twenty-fourth century and the ancestor this started with living in the seventeenth century.[[hottip:* :It is established that the Howard family is from Scotland, where it was commonplace for women to keep their maiden names until the twentieth century. However, the premise is still logically flawed as it requires that the Howard women passed their maiden name on to their daughters.]] Not to mention what would happen if a Howard woman failed to produce a daughter. (Would Ronin have to move onto [[CreatorsPet Wesley]] after Dr. Crusher died?)

** Seemingly averted in ''FireEmblemAwakening'', as the descendants of Ylisse's first Exalt all bear the Mark of Naga, and those with the mark can both wield the [[ForgottenSuperweapon Falchion]] and perform the Awakening Ritual. [[spoiler:Chrom's younger sister Lissa does not have the mark, having her fear that she was a [[HeroicBastard bastard child]], but the fact that her KidFromTheFuture]] Owain has it raises questions about why hers never surfaced. Also, in Lucina's support conversations with whomever her sibling is, it is covertly revealed that they can wield Falchion as well, but they never can do it in-game.]]

* Deconstructed in ''Comics/{{Preacher}}''; in order to keep the bloodline of Jesus Christ pure, his children and their offspring were only allowed to mate with each other. The end result, after generations upon generations of this... is a gibbering, deformed freak who barely has a clue what's going on around him.

* ''TheShadow'', the BigBad is the last descendant of Genghis Khan. And now compare this to what is written in the RealLife section.

* One of the conversations in ''VideoGame/PokerNight2'' reveals that Brock Samson of ''TheVentureBrothers'' is one of only two descendants of [[Franchise/EvilDead Ash Williams]]'s one-night stand with Sheila back in the 13th century. Of course, it could be just [[VideoGame/{{Portal}} GLadOS]] messing with them.

* One of the conversations in ''VideoGame/PokerNight2'' reveals that Brock Samson of ''TheVentureBrothers'' is one of only two descendants of [[EvilDead Ash Williams]]'s one-night stand with Sheila back in the 13th century. Of course, it could be just [[VideoGame/{{Portal}} GLadOS]] messing with them.

* When it comes to European royalty, the grand champion of averting this trope might well be Edward I of England (the legendary "Edward Longshanks" of ''Film/{{Braveheart}}'' fame, who lived between 1239 and 1307 and fathered ''sixteen children'', nearly all of whom survived into adulthood and had children themselves. According to geneologists who have studied his family line, the man now has close to four million living descendants around the world (most of them are in the United States, Canada, and Brazil of all places...)

* Subverted trope in TheBible, in that Jesus needs both father ''and'' mother to be both descendants of the entire Davidic dynasty. Through his mother he gets biological descent, and through his adoptive father who has direct male descent he becomes legal heir. Not to mention that Jesus has several brothers (and there's a possibility that his cousins on his mothers side may also have the same descent).

* EnforcedTrope in the {{Nasuverse}}, where magi generally only pass on magic to a single heir, even if they have more than one children, in order to (according to Tohsaka Tokiomi) discourage magic-related SiblingRivalry (the Aozaki siblings are an exception to this, but then again, they also seem to have decided that they can't coexist in the same universe). DefiedTrope in the case of Tohsaka Tokiomi, who upon siring two talented daughters, made Rin his heir and gave Sakura to be the heir to the heir-less Matou house.

* Not so in Creator/JRRTolkien's ''TheLordOfTheRings'', where multiple lines and descendants exist. An example are the kingdoms of Arnor and Gondor, respectively founded by Elendil and his sons, who are descended from a sideline branch of the Numenorean royal family: in both cases there are various people (both properly royal and more mundane ones) appearing and mentioned as descending from the same ancestor as the "main descendant(s)" of that line. Gondor even eventually [[SuccessionCrisis endured a civil war over the question of inheritance, had problems with multiple potential claimants, and eventually no viable successor could be found who would have pleased everyone, resulting in the Stewards taking over]]. When the Gondorians first had trouble finding a royal successor, the Arnorian line and kingdom was still fully intact, and the Arnorian king tried to take over (on account of both dynasties being descended from Elendil and being married to the last Gondorian king's daughter) but was rejected. His descendant Aragorn would later succeed where he had failed.

* 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), but that all goes to hell when it comes to Marta. She's still the holder of the bloodline even though she has ''a freaking son''. [[PlotHole It really makes no sense]].