History Main / CainAndAbelAndSeth

* ''Series/{{Charmed|1998}}'' revolved around three sisters, the [[TitleDrop Charmed Ones]]. One of the sisters died early in the show, so a half-sister was added down the line to complete the trio. The two elder sisters (Piper and Phoebe) tried to enlist the help of the new sister (Paige), who was reluctant to join them and almost joined the {{Dark Side}}. There were also episodes that focused on how Paige's personality affected the dynamics within the family (namely, an episode where Paige tries to rearrange everything in the house which causes tension between her and Piper). Paige was also far more emotional on decisions concerning the past of their grandparents.

* In ''ComicBook/XMen'', a slip-up by Mr. Sinister introduced an example. As explained on the TangledFamilyTree page, Scott Summers was introduced as an orphan, then met and established a relationship with his brother Alex. This lasted for quite some time before Sinister hinted that there was at least one more brother out there. After a lot of plot changes and WordOfGod statements, the brother was set as Vulcan, a supervillain emperor. But of course, given that Sinister never gave a specific number (he merely said "brothers"), any or all of the other implied candidates could still ''also'' be Summers brothers.

In this trope, a third person, mainly a BigBrotherBully or an AnnoyingYoungerSibling, is introduced specifically in a way to complicate the relationship between established siblings, or between the established siblings and the new sibling, [[CainAndAbel hostile]] [[SiblingRivalry or]] [[SiblingTeam not]]. If the characters aren't related by blood, but through the same MetaOrigin consider themselves BloodBrothers or BashBrothers ''literally'', then another character with the same MetaOrigin and honorary sibling status may suffice.

* In ''Manga/OnePiece'', Luffy and Ace are revealed [[spoiler:to not be related, and have a third [[BloodBrothers Blood Brother]] named Sabo. In their youth, he was the physical midpoint of the three and was TheSpock in their three-man band. The story is told entirely through flashback, as Sabo is assumed dead and thus a PosthumousCharacter. His death and Ace's subsequent death]] complicates every ''previous'' interaction between Luffy and Ace, their current situation, and [[GallowsHumor all those that would follow]]. Additionally, Ace's tattoo and Luffy and Ace's relationships with their TrueCompanions take new significance. In a cover, it is shown that [[spoiler:had Sabo lived, the three would be together, and to cement this "Good Future", Ace's tattoo loses its meaningful misspelling. It becomes further complicated when it's revealed that Sabo ''survived'' the incident that supposedly took his life, and has been in hiding for the last twelve years, apparently as a member of the Revolutionary Army. While undoubtedly a heartwarming revelation, it becomes HarsherInHindsight when one realizes that Ace died without ever knowing that his other brother was alive. And even moreso because Sabo had amnesia the whole time, only remembering his life with Ace and Luffy upon learning of Ace's death... at which point he collapses in tears because he wasn't there to even attempt to save his brother.]]

** ''VideoGame/FireEmblemThracia776 features a more traditional example in [[spoiler: Saias, Julius and Julia's ''other'' half-brother, this time via their father. Saias is the inheritor of Arvis's major Fjalar blood but has the least involvement in the war of the four siblings.]]

* Played about as straight as it can be with Cain (the BigBad), Abel (TheHero), and (TheHighQueen) Seth from ''Literature/TrinityBlood''. Each also [[SpellMyNameWithAnS spells their last name differently]] to reflect their different personalities and roles.

* ''VideoGame/BlazBlue'' have Ragna, Jin, and their sister Saya. Saya was kidnapped 10 years before the start of the story and is nowhere to be seen in the present, both Ragna and Jin assuming that she was long dead. [[spoiler:The ending of the second game came and revealed that she was very much alive and now the head of TheEmpire subjugating the world, additionally she's also possessed by a death god. So both brothers have to put aside their own animosity for each other and deal with their sister.]]
* ''VideoGame/FEAR3'''s [[spoiler:Third Child]] is hinted in the good ending to have a brighter future than [[spoiler:its brothers.]]

* In Literature/TheMoomins, It is common knowledge that Little My and Mymble Jr are siblings. However, the 3rd book reveals that Snufkin’s parents are Joxter and Mymble Sr, meaning that he’s their half sibling. This adds a whole new level of uncomfortable to the scene in the 90’s anime where Little My says to Snufkin that [[SurpriseIncest she wants to date him.]]

* In ''VideoGame/MortalKombatArmageddon'' Rain's ending [[spoiler:revealed he is the third son of Argus - the other two being his paternal half-brothers and rivals Daegon and Taven.]]

* In ''VideoGame/MortalKombatArmageddon'' Rain's ending [[spoiler:it is revealed he is the third son of Argus - the other two being his paternal half-brothers and rivals Daegon and Taven.]]