Innocuously Important Episode / Anime & Manga

• Bloom Into You:
  • Chapter 24. Touko and Yuu's date to the aquarium involves them buying matching charms, which they put on their bags after they start going out.
  • Chapter 27. At first, it merely seems to conclude the Akari/Oogaki subplot, but several chapters later, it's shown as an example of how differently Yuu and Akari take the (apparent) rejection by the person they like. The fact that Yuu doesn't grieve the same way Akari does makes her wonder if she ever loved Touko.
  • Chapter 33 seems like a Breather Episode at first glance, but Rei's story about how she got into a relationship with Hiro seemingly leads Yuu to confess to Touko.
• Case Closed: The anime adaptation of Detective Conan took a lot of liberties from the very beginning. This turned out to be problematic when a seemingly unimportant case from early on (which had been adapted in the episode "Mystery Mastermind" and altered so one minor character does not die) turned out to be very important: The minor character was Ai Haibara's sister and her death triggered her sister's Heel–Face Turn. Ai then becomes a main character, one of the few people that know Shinichi's secret and the only one in the same situation. When the manga reached this point in the story the anime had to create a filler - "The Black Organization: 1 Billion Yen Robbery Case" - that told the exact same story with the same names and everything of "Mystery Mastermind", only with Ai's sister dying. Hence, a lot of confusion.
• A Certain Scientific Railgun: The Jailbreak arc is a Breather Arc where a juvenile detention center releases an open challenge to test their new security. A few hundred people try to break in using various silly means, and face off against the various silly security devices. Unlike most of Academy City, this isn't a front for something evil, the director just genuinely wants to show off. It all ends with the reveal that Uiharu hacked through security, walked in, and then walked out again with the fake prisoner. The director has to eat a lot of crow and pay out the reward he offered. The twist is that the fake prisoner was swapped with a real prisoner, a secret eighth Level 5 who is quite possibly the most dangerous person in the world. And the second in command of the detention, who was working with the prisoner, set everything up so that a hacker would win—allowing them to find the best hacker in the city. They kidnap Uiharu to force her to do a job for the escaped prisoner.
• Code Geass has this with its Breather Episodes, the endings of which containing shocking revelations that set up major changes in the story going forward. The first season's "The School Festival Declaration" is a comedic episode that focuses on hijinks as Lelouch struggles to balance his duties with the Black Knights with his civilian guise amidst an attempt to bake a giant pizza, until the episode ends with his sister Euphemia suddenly announcing her intent to build the "Special Administrative Zone of Japan" for the Japanese people in the occupied Area 11, potentially threatening Lelouch's own plans in so doing and setting into motion the season's explosive climax.
• Cowboy Bebop has the episode Sympathy for the Devil. The first time through the episode might seem to be just another episodic romp, abet one with an immortal creepy kid. However, the episode not only hints at Spike's cyborg eye, but it also has a lot of parallels with the finale, from a villain who Spike's not that different from to Faye wishing Spike off as he's about to go on a presumably fatal mission, to Spike ending the episode pointing his finger like a gun and saying "Bang".
• Dragon Ball:
  • In the early portion of the Red Ribbon Army arc, Goku meets a robot/cyborg named Android 8, who briefly helps him out in Muscle Tower. Many years later, we would meet Android 8's creator, who sets into motion the entire Android/Cell arc and the major events that happen because of it.
  • During the 23rd Tenkaichi Budokai arc, Piccolo and Kami speak to each other in a language nobody but they understand. In one of the few pieces of intentional foreshadowing, said language is written in a distinctly sci-fi alien font, hinting at the later revelation that they're Namekians.
• Fullmetal Alchemist loves doing this. The only even slightly minor character who has only one appearance was the terrorist from the fourth chapter. Even he shows up again. Both Bald (and Colonel Genz from the video game) appear in an advertisement for automail in chapter seventeen.
  • In Fullmetal Alchemist (2003), you didn't think Russell and Fletcher would be content helping Bellsio with his farm for the rest of the show, did you? It seems Russell enjoys borrowing Ed's identity a bit too much. Too bad the second time he does it, the homunculi have Ed pegged as an enemy after the events of Lior. Also there's Rose.
  • The Brotherhood anime has an original story for its first episode, showing the characters chasing and fighting a rogue State Alchemist called Isaac, who is on an anti-government rampage because he doesn't trust the Amestrian higher-ups. He fails as you would expect a filler villain would. In fact, you would be forgiven if you thought this episode is pure filler to introduce newcomers to the series. However, it is full of Foreshadowing: everything Isaac says about the Amestrian government is spot-on, it introduces several characters (like Kimblee) dozens of episodes before they become relevant to the plot, and even his grand plan to freeze the city with alchemy (by creating a city-wide transmutation circle made up of smaller circles) foreshadows the climax of the entire series!
• The heartbreaking episode Affection in Ghost in the Shell: Stand Alone Complex is seemingly an episode made to highlight some of The Major's tragic backstory. Turns out it also tells Kuze's backstory too, and explains how he and The Major met when they were much younger. This does not become explicitly apparent until the final episode of the series, and doesn't become apparent to Motoko herself until right before the final scene of that episode.
• Gintama: Remember episode 13 where the Yorozuya is tasked to find a girl who ran away from home? Turns out she got addicted to a drug made by the Harusame, one of the largest space pirates in the galaxy. Gintoki and Katsura raid the base in order to save Shinpachi and Kagura and in the process give them a bad reputation against the group. The next episode reveals the Bafuku's involvement with the Harusame and how the pirates have the earth and Kabukicho in their sights thanks to the fallout. Their actions also allow Takasugi to set up a deal with them, and later establish an alliance with Kamui and the Bafuku. This also allows some villains connected to them to learn who they are in the future arcs, such as Hosen, the Tendoshuu, and the Naraku.
• In the Haruhi Suzumiya light novels, Endless Eight was exactly this. This short story gave the motivation for the whole fourth book, which most people didn't pick up on. So Kyoto Animation went all out and made EIGHT episodes out of it, setting up the Disappearance movie.
• Kaguya-sama: Love Is War does this a lot. One particular example would be chapter 15, where Shirogane accidentally gropes Kaguya when he gets spooked by a cockroach. Over 150 chapters later, Kashiwagi hears about the groping without any other context after having just been informed that the two started dating. Fearing that Kaguya might develop some weird fetishes if she doesn't follow the normal progression of romance, she gives her a porn DVD how proper sex is supposed to go. Maki ends up helping her set it up and while they're getting it ready to play they end up having a heart to heart that finally ends their decade long rivalry. This in turn would lay the groundwork for ending the feud between their families that had been going on for generations.
• Madlax pulled this off with its Beach Episode, of all things, wherein Vanessa discovers that her employer is in cahoots with Enfant and eventually follows the clues all the way to Gazth-Sonika, unwittingly facilitating the meeting of the series' main protagonists, Margaret and Madlax.
• Episode 3 of Magical Girl Lyrical Nanoha seems like a standard Monster of the Week plot (especially because the series abandons that format with the introduction of Fate the following episode), but it's probably one of the most important episodes in the entire franchise. It established Nanoha's habit of pushing herself to the point of exhaustion (something that would come back to bite her hard), showed the beginning of her signature fighting style, and saw the creation of the Area Search spell.
• Magic Knight Rayearth:
  • The anime has an early episode in which the girls find and befriend an adorable injured animal, unaware that it's really Ascot's latest monster in disguise. In the end, clearly torn about attacking its new friends, the creature nonetheless reverts to its monster form and attacks the girls; they are forced to kill it, which traumatizes them. At first blush, this is just one more filler episode in a long and rather tedious stretch of same. However, it turns out that this episode is major foreshadowing about what the Magic Knights' true mission in Cephiro really is, and what they're going to have to do at the very end...
  • After Caldina does a Heel–Face Turn, she tells Fuu that at least the Magic Knights have a goal — as compared to Zagato, whose reason for this hullabaloo is unknown. Until then, the three girls had genuinely thought that Zagato was simply out to take over Cephiro. Nothing else is mentioned about this for now, and the Magic Knights continue their mission. This is one of the first hints that there will be a Wham Episode coming up.
• In Naruto, the 'Kakashi Gaiden' arc was, for the longest time, just considered to be some interesting Filler that covered some of the backstory of Kakashi and explained where he got his Sharingan eye and somewhat "eccentric" mannerisms, put in between the pre- and post-timeskip stories as a sort of Breather Episode. With The Reveal that Tobi is really Uchiha Obito, who we saw die in that arc it becomes apparent that it was actually the introduction and backstory for one of the series' two joint-Big Bads!
• While One Piece author Eiichiro Oda is a past master of the Chekhov's Gun, one instance that hits this trope is the Skypiea arc, a largely standalone arc with no immediate connection to the primary story except for the near-end reveal that Gold Roger had been there himself. At least four very important things derive from this arc, however:
  1. The treasure obtained in this arc is used to purchase the materials for the Straw Hats' new ship, the Thousand Sunny.
  2. During Skypiea we see several characters with a Combat Clairvoyance power called "Mantra." Five arcs later, at Amazon Lily, we get implications that Mantra is, in fact, the first overt in-story use of a power known as Haki. Some time after that it's outright confirmed that Mantra is the name by which Skypieans know the "Color of Observation" form of Haki. After a Time Skip, several of the Straw Hats learn to use it.
  3. Skypiea introduces and is the source of Dials, a Bamboo Technology that main character Usopp then adopts and uses extensively until Usopp acquires the Pop Greens, as well as spawning a technological revolution that provides easier oceanic transportation and even a music industry that another main character, Brook, becomes a part of.
  4. In Eneru's cover story, the reader is shown that he and the other winged people of Skypiea and Shandia had ancestors on the Moon and left extremely advanced technology there, including a robot army, so advanced that it's coveted by pirates from other planets. His cover story ends with Eneru and his robots readying up to return back to Earth, indicating a larger importance not only to Eneru, but also connects the winged people of the series to the Moon and to the ancient history the World Government tries to suppress at all costs.
  • The battle between Ace and Blackbeard at the tail end of the Enies Lobby Arc. The events and repercussions of the battle set up the single biggest conflict of the first half of the series later on.
  • The scene during the Alabasta arc when Ace parts ways with the Straw Hats, giving Luffy a piece of paper. For a good long while, it appears to be nothing more than an ordinary piece of paper, until at the end of the Thriller Bark Arc, Lola gives one to Nami, explains that this is a special type of paper called a Vivre Card, and Luffy realizes it's just like his. He later sees that the card is beginning to burn and shrink, indicating Ace's life force is waning. But since Ace doesn't like people to fight his battles for him, and the burning down can reverse if the person is stronger, Luffy writes it off, which is a HUGE mistake in the long run when he learns Ace has been sold out by Blackbeard and sent to Impel Down.
  • Ace also mentions seeking out Blackbeard, a traitor to Whitebeard's crew who killed one of his crewmates. Drum Island Arc makes a passing mention to him and four other crewmates going on a rampage there, causing Wapol to lose his kingdom. In the Jaya Arc, there are several unusual people in Mock Town who could be confused for the local colors and general riff-raff. Then Luffy meets a complete stranger who shares similar ideals to his, and outwardly seems like a pretty likable guy, becoming a friendly acquaintance of Luffy's... until he suddenly decks Sarkies of the Bellamy Pirates without breaking a sweat and tries (unsuccessfully) to claim Straw Hat's bounty for himself. Turns out he's Blackbeard, and is a backstabbing two-faced fiend, and those people from Mock Town are part of his crew, while another is off lobbying to get him a seat among the Seven Warlords. Nobody outside of Whitebeard's crew knows who he is since he's a relative upstart among pirates, but after Ace tracks him down and they finally fight, following the aftermath of the battle, everyone knows who Blackbeard is. By Impel Down/Marineford Arc, Luffy learns the truth about him, and it packs a wallop.
  • When Sanji recalls hearing the story of "Noland the Liar," the others point out that it was published in the North Blue, prompting him to explain that while he joined up with the crew in the East Blue, he was actually born in the North Blue. Hundreds of chapters later, we find that he was born to the notorious Vinsmoke Family, a nuclear family made of Mad Scientists and Gadgeteer Geniuses who took over the entire North Blue in the past and gained enough influence for the World Government to recognize them as nobility. They had finally tracked Sanji down and stuck him into an Arranged Marriage so the Vinsmokes can gain further power in the New World through one of its emperors.
  • The Laboon arc initially seems like a mere lead-in to the Whiskey Peak arc, which may have been one reason why the 4Kids dub cut out the arc (along with it involving Luffy attacking a whale). In reality, Laboon is very significant, since a few hundred chapters later, one of his old friends, Brook, joins the Straw Hats, hoping to return to Laboon someday.
• Pokémon: The Series:
  • The Diamond and Pearl episode "Noodles Roamin' Off", Meowth finds out his Fury Swipes give him culinary ability. This seemingly just builds to a one off story where he becomes a noodle chef, only to quit by the end of the episode. However Meowth would continue developing and using this talent in several of Jessie's coordinator events later on.
  • Another Diamond and Pearl episode "The Thief That Keeps On Thieving!" reveals that Jessie and James' careers as Team Rocket's agents have dwindled so badly that Giovanni has forgotten who they are. This ends up coming into play at the end of the Diamond and Pearl series, since Giovanni forgetting their previous failures leads to them being offered the Unova promotion.
• Episode 33 of Revolutionary Girl Utena is one of the several recap episodes. While Utena's recap episodes tend to have some significance, such as explaining (some of) the weirdness behind Nanami's fillers, this episode contains Utena's loss of her virginity to Akio, the event that sets in motion the Apocalypse arc that makes up the final 6 episodes of the series.
• Science Ninja Team Gatchaman: Episode 20, "A Critical Moment for the Science Ninja Team," seems like a typically bad filler episode in which Joe is struck in the head by shrapnel while saving a puppy. The shrapnel is dislodged at the end of the episode and all is good, right? Right? Turns out the shrapnel left Joe with brain damage leading to his illness later on and Disney Death in the finale.
• Space☆Dandy episode "I Can't Be the Only One, Baby" doesn't seem important at first, but it does answer quite a few questions about Dandy's true nature, specifically his Multiple-Choice Past and why the Golgol Empire is hunting him, that are fleshed out in the finale.
• Steins;Gate: The first episode introduces the characters and setting, and begins to get into the concepts of time-travel used throughout the series, but the events of that episode also turn out to have far more significance than they'd seem. Okarin's time-travelling efforts in the final episodes show the events of that day as they truly unfolded, and towards the end of the last episode Okarin watches his past self discover Kurisu seemingly dead, remarking that he was to begin the most important 3 weeks of his life.
• Str.A.In.: Strategic Armored Infantry: The fanservice episode redeems itself by setting up a major plot point that, later on, leads to many a Heroic BSoD, the outing of Sara's identity, the cementing of the True Companions, and the death of one unexpected major character.
• In the Alfheim arc of Sword Art Online, Kirito and Leafa are forced to take a brief detour to Jotunheim at the start of Volume 4, during which they meet Tonky and catch a glimpse of Excalibur. Not only is Excalibur a Chekhov's Gun that is later created and used during Kirito's final confrontation with Oberon at the arc's climax, but the adventure also sets up the later Calibur arc. Unfortunately, this sequence got cut from the anime, so Kirito had to recap it midway through the second season.
• Tengen Toppa Gurren Lagann: Episode Five seemed like a fairly basic Released to Elsewhere plot made in order to add to the adventuring party, but the themes in that episode proceed to permeate the entire third quarter with glorious darkness. When humanity faces a similar situation, in which the population going above a certain total will invite disaster, Rossiu's solution contains the same cold pragmatism that the priest's "lottery" did, and Simon even compares Rossiu to that priest.
• Tiger & Bunny: Episode 14 sees something unexpected happen to one of the heroes that seems like good news at first when Kotetsu suddenly gets a spike in his NEXT powers, albeit at the cost of his Hour of Power expiring slightly sooner than anticipated. Come The Stinger of the following episode, however, it is revealed this is a prelude to something far more dire: sudden power spikes preceded a rare phenomenon where a NEXT loses their powers. The same thing happened to Kotetsu's personal hero, Mr. Legend, and it led to his the end of his career, downward spiral, and eventual death. In any case, one thing is clear: Kotetsu's career as a superhero is going to end sooner than he had hoped.
• Episode seven of Tokyo Magnitude 8.0 seems like a perfectly positive enough filler episode depicting how Mirai has grown and the beginning of a Sick Arc for Yuuki. That is until the last moment when Yuuki collapses. In the next episode he is brought to a hospital but subcumbs to his cranial injuries.
• Chapters 9 and 10 of the Yu-Gi-Oh! manga, where Yugi duels Kaiba for the first time. What at first appears to be a simple Monster of the Week plot leads, directly or indirectly, to every following story arc, the two anime's greater focus on the card game, and the anime spinoffs.
• Toei's Yu-Gi-Oh! (first anime series) has episode 19. While the overall plot is unrelated to the overarching story, Ryou Bakura appears, causing Yugi to wonder about himself and his other self, and Mokuba cameos at the end to signal preparation for the Death-T arc.
• Yu-Gi-Oh! SEVENS lives and breathes with this trope. Many episodes that come across as Filler almost always set up plot points going forward; you'd think that the fifth episode where the heroes have to stop their local school newspaper smearing the Rush Dueling format would be a one and done affair, but the newspaper itself proves to be critical in spreading word of both the format and notoriety for deuteragonist Luke.

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