History Main / SmallRoleBigImpact

* Lily Evans really isn't in much of ''HarryPotter'', but her actions drove the entire characterization of [[spoiler:Snape]], and her HeroicSacrifice set up the entire plot.
** Narcissa Malfoy in the latter ''HarryPotter'' books. In terms of facetime and notoriety, she takes backseat to her husband and son and mostly just another snobby wizard supremacist. However, in [[HarryPotterAndTheHalfBloodPrince the sixth book]], her binding Snape to the Unbreakable vow is ultimately responsible for the climax of the story. And in book 7, her willingness to [[MamaBear lie to]] [[BigBad Voldemort]] about Harry's death is what gives Harry the chance to end him once and for all.

* [[spoiler:Grisha Jaeger]] of ''Manga/AttackOnTitan''. No one has seen hide nor hair of him since very early in the series. Even so, [[spoiler:it's heavily implied to know many mysteries about the Titans, and is suspected to the be the one who gave Eren his Titan Shifting powers, via a mysterious injection.]]

* "Frightening" Frank McCay in ''WesternAnimation/MonstersUniversity'' only shows up in the beginning of the film but he is the one who encouraged Mike to become a scarer in the first place, thus setting off the plot of this film and [[MonstersInc the next one]].

* As pointed out by a rather munted Tim in {{Spaced}}, almost the entire original StarWars trilogy only occurs because of one unnamed character's action; the officer on the Star Destroyer who tells the gunner not to fire on the escape pod with R2D2 and C3PO in it because there are no life-forms aboard. If he had opted to do a little impromptu target practice instead, the droids would never have met Luke, who would thus never have met Ben, no-one rescues Princess Leia, the Death Star plans never make it to the Rebel Alliance...

* Clarisse [=McClellan=] from ''{{Fahrenheit451}}'' [[NeverFoundTheBody is obscurely written out of the story]] ''very'' early on; however, her influence on Guy Montag instigates the entire plot and every event that happens therein.

* Clarisse McClellan from ''Fahrenheit451'' [[NeverFoundTheBody is obscurely written out of the story]] ''very'' early on; however, her influence on Guy Montag instigates the entire plot and every event that happens therein.

* Clarisse McClellan in ''Fahrenheit451'' [[NeverFoundTheBody disappears from the story]] ''very'' early on; however, her influence on Guy Montag instigates the entire plot and every event that happens therein.

-->-- '''BruceCampbell''', ''If Chins Could Kill: Confessions of a B-Movie Actor''

* [[SteveBuscemi Mink]] in ''MillersCrossing'' only has two short scenes(one of those over the phone), and yet his "[[LoveTriangle relationship]]" with both [[JohnTurturro Bernie]] and Eddie Dane sets off a large part of the plot.

* The ''Literature/LordOfTheRings'' books are full of this. You have characters like Erkenbrand, a Marshall of Rohan leading the troops that Gandalf collects to save everyone at Helms Depp, or Ghan-buri-Ghan, a NobleSavage tribesman who leads the Rohirrim around an ambush so they can arrive at the Battle of the Pelennor Fields in time and at full strength.
* Arianna Ortega in the ''DresdenFiles'' interacts only with Harry, and appears in a grand total of three chapters before biting it. Her plans result in Harry damning his soul forever, and sets the plots for book 12 and 13 in motion.

* The StoryWithinAStory in ''HansBrinkerOrTheSilverSkates'' about a boy plugging a dike with his finger and preventing a flood is more famous than the actual story of Hans Brinker and his skates.

* Bane in ''BatmanArkhamAsylum''. His only appearance is a brief, yet [[CrowningMomentOfAwesome epic]] confrontation, but [[spoiler: his Venom serum]] is basically the catalyst for the entire game's plot.
* The "Oriental Gentleman" from ''VideoGame/GrandTheftAutoIII'', an [[NoNameGiven unnamed]] man who just so happens to be a prisoner in the same police convoy the player character is in - the fact that the game consists of typical ''VideoGame/GrandTheftAuto'' fare rather than the player being behind bars for the whole game (or at least a few minutes, considering the series) is due entirely to the fact that the Colombian Cartel decided to hold up the convoy and take this one prisoner.

* The ''Literature/LordOfTheRings'' books are full of this. You have things like Erkenbrand, a Marshall of Rohan leading the troops that Gandalf collects to save everyone at Helms Depp, or Ghan-buri-Ghan, a NobleSavage tribesman who leads the Rohirrim around an ambush so they can arrive at the Battle of the Pelennor Fields in time and at full strength.

* The Little Green Men in ''WesternAnimation/ToyStory 3''.
* Edna Mode from ''TheIncredibles''. She appears three times, all in the first half of the film. She's the one who alerts Helen to her husband's moonlighting hero work, and convinces Helen to go track Bob down.
* Ellie in ''Film/{{Up}}'', whose death is responsible for Carl's attitude for most of the film, and the real estate agents who drive Carl to fly his house to South America.

* ''Series/DoctorWho'': The undeniably heroic Harriet Jones, Prime Minister (yes, [[RunningGag we know who she is]]), played by the inimitable Penelope Wilton, appears in a grand total of four episodes. In the third of those, the Doctor's reaction to something she does changes the entire course of history and has serious consequences for the next three seasons of that show and all of ''Series/Torchwood''. Then, despite having been thoroughly screwed over by said Doctor, she proceeds to help save the world with a [[TearJerker tear-jerking]] HeroicSacrifice. She's also a [[OneSceneWonder Four-episode Wonder]], as she's one of the most iconic supporting characters of the new series and a fan favourite.

* ''Series/DoctorWho'': The undeniably heroic Harriet Jones, Prime Minister (yes, [[RunningGag we know who she is]]), played by the inimitable Penelope Wilton, appears in a grand total of four episodes. In the third of those, the Doctor's reaction to something she does changes the entire course of history and has serious consequences for the next three seasons of that show and all of ''Series/Torchwood''. She's also a [[OneSceneWonder Four-episode Wonder]]; she's one of the most iconic supporting characters of the new series and a fan favourite.

* ''Series/DoctorWho'': The undeniably heroic Harriet Jones, Prime Minister (yes, [[RunningGag we know who she is]]), played by the inimitable Penelope Wilton, appears in a grand total of four episodes. In the third of those, the Doctor's reaction to something she does changes the entire course of history and has serious consequences for the next three seasons of that show and all of ''Series/Torchwood''.

** Also Kara, Mordred's GirlOfTheWeek whose execution at Arthur's behest starts the DisasterDominoes that leads directly to his FaceHeelTurn and the GrandFinale.

* The StoryWithinAStory in ''HansBrinkerOrTheSilverSkates'' about a boy plugging a dyke with his finger and preventing a flood is more famous than the actual story of Hans Brinker and his skates.

* Ellie in ''Film/{{Up}}''.

* Arianna Ortega in the Dresden files interacts only with Harry, and appears in a grand total of three chapters before biting it. Her plans result in Harry damning his soul forever, and sets the plots for book 12 and 13 in motion.

* The StoryWithinAStory in HansBrinkerOrTheSilverSkates about a boy plugging a dyke with his finger and preventing a flood is more famous than the actual story of Hans Brinker and his skates.

* High Templar Karass of VideoGame/StarcraftII fame. He and his men meet up with Zeratul, help him fight through the zerg, and then he and his remaining troops pull a LastStand HeroicSacrifice to allow Zeratul to escape. Yet those few minutes, he and his men might have saved the universe.

* Tomoo from Elfen Leid appears in one episode and one manga chapter, but it was his actions that ultimately played the biggest role in turning Lucy into a bitter figure who hated humanity (namely he beat her puppy to death with a rock/vase.) Lucy snapped and brutally executed him and his cronies, as well as someone who may or may not have meant to betray her. After that it was all down hill

* The Emperor in ''{{Onmyoji}}'' is hardly in it bar a couple of scenes in which he does very little that's useful, but it's his rejection of Suke-hime that leads to most of the villain's attempts to kill the imperial family via her angry father and her eventual transformation into a demon.