History ChekhovsGun / HarryPotter

If the ChekhovsArmoury in ''Literature/HarryPotter'' were an actual armory, it would curbstomp everyone in a massive ZergRush, and possibly hand the victory to our heroes without even trying. Please list examples by the book in which the "gun" was introduced.

If the ChekhovsArmoury in ''Literature/HarryPotter'' were an actual army, it would curbstomp everyone in a massive ZergRush, and possibly hand the victory to our heroes without even trying. Please list examples by the book in which the "gun" was introduced.

* Hagrid mentions Voldemort's followers, who are not identified as Death Eaters until ''Goblet of Fire''. He also vaguely describes the First Wizarding War, which is elaborated on significantly in ''Order of the Phoenix''. Furthermore, Hagrid mentions the Bones and Prewett families, members of which later appear in the series (Molly Weasley and Susan Bones later in this book and Amelia Bones in ''Order of the Phoenix''), and the [=McKinnons=], all of whose deaths are elaborated on in ''Order of the Phoenix''.
** Molly's twin sons Fred and George were given the same initials as Molly's late brothers Fabian and Gideon, who died fighting ''five'' Death Eaters, including Antonin Dolohov.

* Hagrid says that some of Voldemort's followers came out of trances, which is revealed to be caused by the Imperius Curse in ''Goblet of Fire''.

* Hagrid says that Dumbledore declined to become Minister for Magic, but the actual reason is not revealed until ''Deathly Hallows''. He also mentions Cornelius Fudge, who appears in ''Chamber of Secrets'' and remains an important character until ''Half-Blood Prince''.
* Harry's course books include ''A History of Magic'' by Bathilda Bagshot, who is important in ''Deathly Hallows''.

* The Snitch from Harry's first Quidditch match (he nearly swallowed it) becomes important again towards the end of ''Deathly Hallows''.

* The centaurs reappear in ''Order of the Phoenix'' are important to the plot, exiling Firenze for agreeing to teach at Hogwarts, having tensions with Hagrid for bringing a giant into the forest, disposing of Umbridge due to Hermione's trickery, and then almost killing Harry and Hermione when Hermione admits she was using them.

* Dumbledore sends Harry his father's old invisibility cloak. It is revealed in ''Deathly Hallows'' that the cloak is one of the titular Hallows and why it was in Dumbledore's hands in the first place.

* The Thestrals, and Harry's ability to see them, pay off later in the book when the Golden Trio, plus Neville, Luna, and Ginny, need a way to fly to London.

* The Lovegoods are first mentioned by Amos Diggory as a local wizarding family attending the World Cup. Luna Lovegood becomes a major supporting character in the following books and her father Xenophilius prints Harry’s interview with Rita in ''Order of the Phoenix'' before being properly introduced in ''Deathly Hallows'' where he gives Harry key information on the titular objects.

* The Lovegoods are first mentioned by Amos Diggory as a local wizarding family attending the World Cup. Luna Lovegood becomes a major supporting character in the following books and her father Xenophilius prints Harry’s interview with Rita in ‘’Order of the Phoenix’’ before being properly introduced in ‘’Deathly Hallows’’ where he gives Harry key information on the titular objects.

* [=McGonagall=] mentions Godric's Hollow, which becomes a major location in ''Deathly Hallows'', where we learn that the Dumbledore family and Bathilda Bagshot lived there for a time. It will become crucial as Voldemort knows where to look.

* Fred and George steal a salamander from their Care of Magical Creatures class. Not only does the trio begin taking this class in ''Prisoner of Azkaban'', but the current professor Silvanus Kettleburn retires and is replaced by Hagrid.

* Ernie Macmillian, Hannah Abbot, and Justin Finch Fletchley, become important characters later on in the series. Ernie, Hannah, and Justin support Cedric Diggory in "The Goblet of Fire"; and they later join Dumbledore's Army when it is started in "The Order of the Pheonix" and continues in "The Half-Blood Prince" and "Deathly Hallows". Ernie also becomes friends with Harry, Ron, and Hermione during that book and "The Half-Blood Prince" when they all are in Slughorn's N.E.W.T Level Potions Class.
* Terry Boot is mentioned by his last name by Lockhart during the Dueling Club. He later becomes a more prominent character later on. In "Order of the Phoenix", he joins Dumbledore's Army and reveals to Harry his knowledge of him killing the Basilisk with Gryffindor's Sword. in "The Half-Blood Prince" He, Harry, Ron, Hermione, Draco, Ernie, and fellow Ravenclaw Michael Corner are the only ones in Slughorn's N.E.W.T level Potions class, and in "The Deathly Hallows", he and the other Ravenclaws in the DA tell Harry about Rowena Ravenclaw's lost Diadem.

* When Harry hides his potions book in the Room of Requirement, he marks the spot with a bust of a warlock wearing a wig and an old, battered tiara. Said tiara becomes immensely important in Book 7 when it's revealed to be the Lost Diadem of Ravenclaw, one of Voldemort's Horcruxes.

* Dumbledore send Harry his father's old invisibility cloak. Is revealed in ''Deathly Hallows'' that the cloak is one of the titular Hallows, and why it was in Dumbledore's hands in the first place.

* The flying Ford Anglia is used to take Harry from the Dursley's house. Then again when Harry and Ron miss the Hogwarts Express and fly it to Hogwarts and then for them to escape from the Acromantulas in the Forbidden Forest.

* Fred, George, and Lee Jordan buy Filibuster Fireworks at Gambol and Japes. They shoot some off on the last day of vacation, George forgets the box when they are leaving to go to King's Cross, then he and Fred attempt to feed one to a Salamander at Halloween, and finally Harry uses one to create a diversion in Potions class so Hermione can obtain the last two ingredients they need for the Polyjuice Potion.

* Ron's broken wand, with spells backfiring on him, is mostly used for comic relief throughout the book. However, it ultimately saves Ron' and Harry's memories when Lockhart attempts to obliviate them with it.

* Hermione can't believe that Lockhart is an inept teacher and wizard, she talks about the amazing things he has done. Ron retorts with "He ''says'' he's done." Lockhart himself reveals that he's a fraud, going to the real people who have done the heroic deeds, listening to the exact details and then wiping their memories clean with his speciality, the Memory Loss Charm.
* Draco Malfoy calls Hermione "filthy little Mudblood" and it is stressed upon how highly offensive the term is to Muggleborns. In ''Order of the Phoenix'', we learn that, in the past, Snape called Harry's mother that, which turned her against him and denied him any chance with the woman he was in love with. These events fuel much of Snape's motivation throughout the entire series.

* Hagrid's expulsion from Hogwarts is brought up again, and is explained later in the book.

* Fred and George steal a salamander from their Care of Magical Creatures class. Not only do the trio begin taking this class in ''Prisoner of Azkaban'', the current professor Silvanus Kettleburn retires and is replaced by Hagrid.

* Polyjuice Potion is used relatively innocently here, but later in the series it becomes an important tool for good and for evil.
* Dobby tells Harry that if he can only be freed if his masters present him with clothes, and that if he was presented with even a sock, he would be free to leave his masters' house forever. At the end, Harry tricks Lucius Malfoy into doing just that (with a sock), releasing Dobby from servitude.
* Dumbledore says the question is not ''who'' opened the Chamber of Secrets again, but ''how''. He already knows that Tom Riddle opened it in the first place, he just doesn't have any evidence to prove it, and can't explain how he's managed it this time.
* Seamus says that dueling lessons "might come in handy one of these days..." Indeed they do, when the Second Wizarding War begins.

* When Harry meets Fawkes, Dumbledore explains that Phoenixes can carry enormous weight and their tears have healing powers, both of which are very useful later in the book. They also regularly die and then return to life, which allows Fawkes to intercept Voldemort's Killing Curse meant for Dumbledore in ''Order of the Phoenix''. Fawkes himself is the Phoenix who gave the feathers for Voldemort' and Harry's wands, as revealed in ''Goblet of Fire''.

* The second years sign up for third year electives. Harry and Ron take the same classes, which are revealed in ''Prisoner of Azkaban'' to be Divination and Care of Magical Creatures, while Hermione signs up for them all, and is revealed late in the next book to have received a Time-Turner at the start of the third year in order to accomplish this.

* Colin Creevey mentions taking photos with his camera. This ends saving his life when he encounters the Basilisk: thanks to seeing the beast through his camera, he ends petrified instead of killed.
* Ernie Macmillian, Hannah Abbot, and Justin Finch Fletchley, Become important characters later on in the series. Ernie, Hannah and Justin support Cedric Diggory in "The Goblet of Fire"; and they later join Dumbledore's Army when it is started in "The Order of the Pheonix" and continues in "The Half Blood Prince" and "Deathly Hallows". Ernie also becomes friends with Harry, Ron and Hermione during that book and "The Half Blood Prince" when they all are in Slughorn's N.E.W.T Level Potions Class.
* Terry Boot is mentioned by his last name by Lockhart during the Dueling club. He later becomes more a prominent character later on. in "Order of the Phoenix" he joins Dumbledore's Army and reveals to Harry his knowledge of him killing the basilisk with Gryffindor's sword. in "The Half Blood Prince" He, Harry, Ron, Hermione, Draco, Ernie, and fellow Ravenclaw, Michael Corner are the only ones in Slughorn's N.E.W.T level Potions class. and in "The Deathly Hallows", he and the other Ravenclaws in the DA tell Harry about Rowena Ravenclaw's lost Diadem.

* Sirius Black is mentioned on a Muggle news broadcast. He is soon revealed to be the eponymous prisoner of Azkaban, and is a major character in the series.

* Professor R.J. Lupin initially just seems to be the new Defense Against the Dark Arts Professor. We later learn that he has a connection to Harry's parents and Sirius Black, and that he is a werewolf.

** Harry's prophecy involving Ron suggests great suffering, followed by great happiness. Ron is traumatized by Voldemort's Locket horcrux, but ultimately earns his happy ending with Hermione.

* Lupin teaches the third years about Grindylows. Harry ends up getting attacked by a swarm of them in ''Goblet of Fire'', and Fleur Delacour fares worse against them, costing her points in the second Triwizard Task. In ''Deathly Hallows'', when Lupin suspects that someone betrayed the escort team, he asked Harry which creature he saw the first time he entered in his office to see if he's the real Harry, and his answer, a Grindylow, is correct.

* Snape substitute teaches Defense Against the Dark Arts several times. In ''Half-Blood Prince'', he gets the job full time.
* Snape teaches the third years about werewolves, and we later learn that he was intentionally doing this in an attempt to out Lupin (Hermione catches on immediately, but doesn't out Lupin).

* Hermione asserts that Harry's Firebolt was sent by Sirius Black as a trick. It turns out [[RightForTheWrongReasons she's right, but for the wrong reasons. It was a genuine gift.]]

* Fudge says that the dementors were out of control when they attempted to Kiss Harry. This hints at how little control the Ministry has over them, and they end up siding with Voldemort in ''Half-Blood Prince''.

* Nagini appears as Voldemort's pet snake. However, she has a more important role in ''Order of the Phoenix'', and in ''Half-Blood Prince'', we learn that she is one of his Horcruxes. The [[Film/FantasticBeasts prequel series]] later reveals she was originally human, but under a Maledictus Curse.
* It is revealed that Peter Pettigrew abducted Bertha Jorkins and that Voldemort murdered her. Her disappearance is important throughout the book, and the information he extracted from her lead to his return to power at the end.

* Voldemort refers to his "''faithful'' servant" rejoining him. Despite implications that it is Igor Karkaroff, we later learn he means Barty Crouch Jr.

* Voldemort kills Frank Bryce with "a flash of green light," same as Harry's parents. Later in the book, this is identified as the Killing Curse.

* Winky the house-elf sits next to an empty seat on the pretense of saving it for her master. It is later revealed that Barty Crouch Jr. was there the whole time under an invisibility cloak.

* Hermione first becomes annoyed at the mistreatment of house-elves, which later leads her to found the Society for the Protection of Elvish Welfare.

* The Ministry responds to Mad-Eye Moody's house because he claims there was an intruder. It later turns out there ''were'' intruders, Peter Pettigrew and Barty Crouch Jr., and the latter began impersonating the real Moody after they captured him. Diggory also mentions that Moody was supposed to be starting his new job that same day, soon revealed to be Defense Against the Dark Arts professor at Hogwarts.

* Moody mentions that he's going against what the Ministry deems appropriate for the fourth year Defense Against the Dark Arts class. In ''Order of the Phoenix'', the Ministry exercises significantly more control over the curriculum when Professor Umbridge is hired, with this being cited as an example.

* Moody lends Neville ''Magical Water Plants of the Mediterranean''. This was Barty Crouch Jr.'s attempt to [[InvokedTrope invoke this trope, assuming that Harry would ask him for help with the Second Task and that Neville would tell him about gillyweed, but it is unsuccessful in the book (though it works in the film).]]

* Harry remembers that his wand and Voldemort's share twin cores, which becomes extremely important at the end of the book.

* Hermione angrily tells Ron at the end of the Yule Ball that if he wanted her to go with him, he should've acted before Krum (or someone else) did and asked her when he had the chance. In "The Deathly Hallows", he rectifies this by asking her to dance with him during Bill and Fleur's wedding before Krum can; she's surprised, but she quite happily accepts.

* Moody suggests that Harry try a career as an Auror. By series' end, he takes N.E.W.T. classes to become an Auror, and eventually ends up becoming one.
* Harry rescues Fleur's little sister, Gabrielle, from the Black Lake. This earns both him and Ron her goodwill, and eventually leads to her marrying Ron's older brother Bill by the time of ''Deathly Hallows'', not to mention Fleur's gratitude also means her's and Bill's door is always open to Harry and Ron, which comes in handy when they're hiding from the Death Eaters.

* Hermione complains about Crouch's unfair treatment of Winky and Sirius says "if you want to know what a man's like, take a good look at how he treats his inferiors, not his equals." In ''Order of the Phoenix'', he treats his own house-elf Kreacher like vermin, which ends up leading to his own death.

* Hagrid gives his class a lesson on nifflers, involving a little game where he hid leprechaun gold underground. The tilled earth allows Barty Crouch Jr. to hide his father's transfigured body without anyone being any the wiser. Nifflers are also used to harass Umbridge in the next book, though Hagrid is endangered by their use as the Care of Magical Creatures teacher (Lee Jordan admits to be the responsible party for this case).

* Harry sees the sword of Gryffindor in Dumbledore's office, having left it there at the end of ''Chamber of Secrets''. He learns why it's still there in ''Half-Blood Prince'' and it becomes critically important in ''Deathly Hallows''.
* Dumbledore's Pensieve makes its first appearance, and is plot-relevant from this point on.

* Karkaroff names Antonin Dolohov, Mulciber, Travers, and Augustus Rookwood, all of whom escape from Azkaban in ''Order of the Phoenix''. In ''Order of the Phoenix'', Rookwood is instrumental in telling Voldemort how to retrieve the prophecy, due to him being a member of the Department of Mysteries, which results in the death of Sirius Black, and in ''Deathly Hallows'', he kills Fred Weasley, and later gets defeated by Aberforth. In that same book, Dolohov kills Remus Lupin, and is later defeated by Filius Flitwick. Another Death Eater named is Evan Rosier, who took a piece of Moody's face with him in a fight to the death.

* It is revealed that Frank and Alice Longbottom were tortured by Death Eaters. They appear in ''Order of the Phoenix'', as do their torturers. One of said torturers (Bellatrix) becomes critically-important to the remainder of this book.

* The murder of Cedric Diggory becomes a major for Harry's character, as the trauma impacts him for the rest of the series. Most immediately, the fact that it happened in front of Harry allows him to see thestrals in ''Order of the Phoenix''.

* Dumbledore tells Fudge that he will go down in history as one of the worst Ministers for Magic if he sticks his head in the sand and denies Voldemort's return. This is exactly what ends up happening at the end of "The Order of the Pheonix" and before the start of "The Half Blood Prince".

* Dumbledore orders Sirius to make contact with "the old crowd," revealed in ''Order of the Phoenix'' to be, well, the Order of the Phoenix. He also mentions Arabella Figg, who turns out to be the same Mrs. Figg as the one who lives in Little Whinging. In the start of "Order of the Phoenix", She and Mundungus Fletcher are assigned to look after Harry.

** Sturgis Podmore is Imperiused by Lucius Malfoy as part of Voldemort's plot to steal the prophecy later in the book, which leads to him being imprisoned, then released.

* Tonks warns Moody that an Auror named Scrimgeour has been asking some rather nosy questions of Tonks and Kingsley. Scrimgeour would be revealed as Rufus Scrimgeour, Head of the Department of Magical Law Enforcement and Fudge's successor as Minister of Magic in the next book, and this trend of nosing into other peoples' business would continue with him constantly attempting to pry into Harry's and Dumbledore's relationship and their secret meetings.

* The thestrals, and Harry's ability to see them, pay off later in the book when the Golden Trio, plus Neville, Luna, and Ginny, need a way to fly to London.
* Hermione makes a list containing the names of all the people agreeing to be in the DA. It's mentioned it that signing it feels unusually binding. Hermione cursed the list so that anyone who revealed the DA to the Ministry would break out in a rash. Not just any rash, either. It (permanently, per WordOfGod) writes 'Sneak' across their face.
* In ''Chamber of Secrets'', a passing mention was made to Peeves breaking a cabinet, preventing Harry from getting into trouble. It's mentioned here again, when the Weasley twins push one of Umbridge's hench-students in, and he gets trapped there for months because it's magical. In the next book, it's revealed to be linked with another cabinet outside the school (namely the same one Harry hid in after a botched Floo Powder transport dumped him out at Borgin and Burkes on Knockturn Alley), and Draco fixes it to let the Death Eaters in.
* "Snape's Worst Memory". It involves Snape being publicly humiliated by Sirius, James and Peter, and provides an interesting AlternativeCharacterInterpretation to James Potter (JerkJock, specifically). It's pretty bad on the surface... but in Book 7, we learn why it was his ''worst'' memory: it was the day he lost Lily forever (due to his own behavior, not really anything James did).

** Regulus Black, Sirius's brother who is mentioned in passing and the becomes important to the plot in Book 7.

** [[FortuneTeller Professor Trelawney]]. In [[Literature/HarryPotterAndThePrisonerofAzkaban Book 3]] Dumbledore casually mentions that he should give her a raise, since the prediction she made about Wormtail turned out to be true, and that it was the second accurate prediction she had ever made. At the end, it's revealed what the first one was.

* When Harry hides his potions book in the Room of Requirement he marked the spot with a bust of a warlock wearing a wig and an old, battered tiara. Said tiara becomes immensely important in Book 7 when it's revealed to be the Lost Diadem of Ravenclaw, one of Voldemort's Horcruxes.

* The tiny bottle of Felix Felicis that Harry wins in his first Advanced Potions lesson is used by Harry to convince Slughorn to give to Harry his memories of when and how much he told Tom Riddle about horcruxes. What is left of it is then used by Harry's friends on the night of Dumbledore's Death to save their lives by making spells miss them by inches.
* Peruvian Instant Darkness Powder. Fred and George show it to Harry when he and the other Weasleys visit their joke shop in Diagon Alley, and mention how it could come in handy if one needs to make a quick escape. Come the end of the book where the school is infiltrated by Death Eaters thanks to Malfoy, and it does exactly that.
* Tonks' Patronus changing its form. The fact that it's supposed to represent Lupin shows that the Patronus often represents someone the caster loves... much like Snape's.
* During this years' only Hogsmeade trip, the trio encounter Mundugus again, selling things he stole from Grimmauld Place. The Hog's Head barman (Aberforth) was talking to him as they approached, and most likely acquired Sirius' mirror at that time, which becomes quite significant in the next book. Not to mention one of the things Mundungus takes from the house is a Horcrux.
* Romilda Vane's love potions, which are hidden in a box of chocolate cauldron cakes. Ron takes them on his birthday, and he falls in love with her, so naturally, Harry takes Ron to Professor Slughorn for a cure, but Prof. Slughorn ends up accidentally giving him poison, which he mentions was meant for Dumbledore.
* The ring that Marvolo Gaunt wore eventually became one of Voldemort's horcruxes. Dumbledore's attempt to destroy it burned his hand and put a curse on him. He only has a year to live, which is why he orders Snape to MercyKill him.

** Marvolo mentions being descended from the Peverell family, from whom he inherited the ring. Cadmus Peverell, creator of the Resurrection Stone, is an ancestor of the House of Gaunt. Even more, Cadmus' younger brother, Ignotus, was not only Harry's ancestor, he's also the creator of Harry's Invisibility Cloak.

** Not to mention the protection charm cast by Lily which protect Harry from Voldemort. Harry's HeroicSacrifice fuels the same charm, protecting ''all the students and staff of Hogwarts''.
* Early in the book, Harry briefly sees someone else's eye in a fragment of Sirius' mirror. It turns out later on to be Aberforth Dumbledore, who purchased the mirror when we saw him in ''Half-Blood Prince''.

* Trelawney's continued obsession with Harry's death finally comes to fruition in this book, though it's the one year where they don't interact until the very end and [[NotQuiteDead it doesn't take anyway]].

* Scamander mentions the "extremists" who want Muggles classified as beasts. This essentially become official policy under the Voldemort-controlled Ministry of Magic in ''Deathly Hallows''.

* There is an entry on ghouls. The Weasley family's ghoul becomes important in ''Deathly Hallows'', when it is disguised as a Spattergroit-infected Ron.
* There is an entry on Nifflers. Nifflers appear in ''Goblet of Fire'', where the dig up lots of earth to find shiny objects as part of a game of Hagrid's making. This is used to disguise Barty Crouch Jr. hiding his father's transfigured body as a bone in the tilled earth.

Terry Boot is mentioned by his last name by Lockhart during the Dueling club. He later becomes more a prominent character later on. in "Order of the Phoenix" he joins Dumbledore's Army and reveals to Harry his knowledge of him killing the basilisk with Gryffindor's sword. in "The Half Blood Prince" He, Harry, Ron, Hermione, Draco, Ernie, and fellow Ravenclaw, Michael Corner are the only ones in Slughorn's N.E.W.T level Potions class. and in "The Deathly Hallows", he and the other Ravenclaws in the DA tell Harry about Rowena Ravenclaw's lost Diadem.

* Ernie Macmillian, Hannah Abbot, and Justin Finch Fletchley, Become important characters later on in the series. Ernie, Hannah and Justin support Cedric Diggory in "The Goblet of Fire"; and they later join Dumbledore's Army when it is started in "The Order of the Pheonix"; Ernie also becomes friends with Harry, Ron and Hermione during that book and "The Half Blood Prince" when they all are in Slughorn's N.E.W.T Level Potions Class. Also according to Rowling, Hannah marries Neville some time after the series' end.

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* Harry finds a book at Flourish and Blotts that mentions the tongue-tying curse, which comes up again in ''Deathly Hallows'' to prevent Snape from revealing the location of 12 Grimmauld Place to the Death Eaters.

** Molly's twin sons Fred and Geroge were given the same initials as Molly's late brothers Fabian and Gideon, who died fighting ''five'' Death Eaters, including Antonin Dolohov.