"Part of the attraction of The Lord of the Rings is, I think, due to the glimpses of a large history in the background: an attraction like that of viewing far off an unvisited island, or seeing the towers of a distant city gleaming in a sunlit mist. To go there is to destroy the magic, unless new unattainable vistas are again revealed."One way of building background is to have the characters refer to things without explaining exactly what those things are. The slight confusion caused is balanced by the sense given of a larger world, outside the plot. If a story is extended to a long enough series (especially when there's a high turnover of writers), most of these cryptic references are explained and/or used as Canon Fodder, but often one or two will never appear in story. What such references really mean is a favorite subject for fan-clubs. The rise of the web has reduced the incidence of such things (creators get asked), though not totally eliminated them. Compare to the closely-related Noodle Incident, Canon Fodder, Narrative Filigree, What Happened to the Mouse? and Mysterious Past. Unknown Character, Great Offscreen War and Cataclysm Backstory are commonly played as sub-tropes of this, as is Famous, Famous, Fictional. See Hufflepuff House for organizations with this treatment more referred to than seen. If the reference in question is actually explained later on, it becomes Foreshadowing, Chekhov's Gun, or Brick Joke. If not, it becomes a Noodle Incident. Interestingly, if you start following a long-running series from the middle (rather than from the start), every Continuity Nod in it effectively becomes a Cryptic Background Reference for you, so it's all just a matter of perspective, really.
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Anime & Manga
- Considering Blame! is a series that prides itself in its sheer vagueness, it isn't a big surprise that this trope shows up at least once a chapter. Technology and factions are seen, mentioned and interacted with often, but in most cases, never fully explained. This adds to the already frighteningly vast feel of the ''verse, and leaves plenty of room for Wild Mass Guessing.
- Cowboy Bebop does this all the time, sometimes without even directly saying anything. It oftentimes does this with the main plot and character traits — e.g. Ein is a "data dog", something apparently important and rare which is only vaguely explained, even in the episode where it's mentioned. This is subtly lampshaded — Jet angrily asks Spike why he's running off to kill a man from his past. Spike pointedly (even cynically) asks him how he lost his arm, causing Jet to clam up. The circumstances behind Spike's pursuit of the man and Jet's lost arm are eventually revealed.
- Eureka Seven:
- This anime features the characters spouting a lot of Engrish phrases that won't mean anything until a good twenty episodes later. It gets pretty confusing when half of the spoken terms have no meaning to the viewer.
- Its sequel, Eureka Seven AO is slightly better. There are a lot of references to events in the past, and several hints that there is something off about the Alternate Universe. They also managed to cut the introduction to meaning rate by about 50%, meaning that almost every truly cryptic and bizarre thing has been given some measure of explanation or meaning within 10 episodes, as opposed to the 20 mentioned above. Yes, if you just started watching, that means that the Alternate Universe thing will get explained very soon.
- Mahou Sensei Negima!:
- A visual one: in the splash page from the first chapter of the manga, look closely at the center. Zazie Rainyday has claws.◊ 250+ chapters later, this is still unexplained, as is everything regarding Zazie. It finally appears in the story proper in chapter 298.
- The Magic World is filled to the brim with this type of stuff, with people referring to all sorts of races, animals, places, and phenomena that don't happen here.
- Puella Magi Madoka Magica:
- A very subtle one. When Mami explains why Witches are bad, she mentioned them luring people to suicide and causing fights to break out in certain places. The second type of bad influence is never seen in the anime.
- It's also hinted that she knew Kyoko, and Kyoko's past — but this is actually confirmed in a Drama CD.
- Several are found in in the manual(s). The official website describes three witches who never appeared in the anime, because only their familiars did. We don't even know what they look like. Then we have the revelation that Walpurgisnacht is only a nickname. It's real name is only listed as "?????".
- In Psycho-Pass, there are very occasional references to the fact that some great catastrophe has happened and Japan, with the aid of the Sybil system, is one of the few relatively normal nations left.
- Slayers has a hierarchy of gods and demons distributed over four universes. Only some of these deities are described, others are named or merely implied. Nothing is known about the demons Chaotic Blue and Death Fog, for instance, and less than that about their opponents. Fanfic authors have, naturally, expended much effort to fill the gaps.
- Sound of the Sky is rife with this trope. Most of the back story can be divided into two categories. There's the information that was lost forever during the Great Off Screen War, which isn't explained since none of the characters are aware of it. And then there are the things that all of them know about, which isn't explained since the characters have no reason to exposit out loud about it when speaking to each other.
- Yokohama Kaidashi Kikou is the Slice of Life story of a Ridiculously Human Robot named Alpha running a small cafe during the twilight of humanity. Numerous mysteries are touched upon but absolutely none are explained fully, either because they have nothing to do with the story as previously outlined, or the characters are just as much in the dark as the readers.
- Astro City uses this trope a lot, especially in the earlier volumes when the universe wasn't so fleshed out. There are constant references to heroes, villains, and incidents that the readers have not seen yet - and sometimes never see, since the story is more about how people think and live in a superhero world than about the actual exploits of the heroes. The author, Kurt Busiek, uses this trope a lot in his work - the same treatment is given to his magic-replaced-technology World War I story Arrowsmith, among others.
- ElfQuest used to do this, but over the years, people Running the Asylum have started to fill in most of the gaps. Whether they should have bothered or not is a matter of some debate.
- The League of Extraordinary Gentlemen does this constantly to fill in the gaps between the novels that the characters first appeared in and the actual LoEG comics themselves. To the point where a reference guide for all of the bits in the first collected comic was three times the thickness of the comic itself. One panel could have two pages worth of 'This is the X from Y', especially in their museum base.
- This pops up in another work by Alan Moore, Promethea. There are several references to adversaries and events from Promethea's past that are never seen or elaborated upon. The Shadow Queen however is probably the most notable since she is referred to several times without any details about her nature or ambitions revealed to the audience.
- A Republic comic showed a Geonosian hive on the ice world Zaadja where several Mandalorian corpses were embedded into the walls. At the time of writing both races had an alliance with the Confederacy which would rule out any logical reason.
- Writer Tristan Huw Jones would pepper his Tales of the TMNT stories with these, particularly when it came to characters.
- James Robert's Transformers stories (The Transformers: Last Stand of the Wreckers, The Transformers: More Than Meets the Eye...) tend to mention things, events, and places that are often very slowly elaborated upon or explained over time, if at all.
- New Avengers (2015): During issue 6, the Avengers of the future mention the "Eternity Wars", which had some part to play in Hulking becoming what they proclaim "King of Space", before adding that it's apparently some time away. Then Collapsar hurriedly asks Sunspot to forget he ever heard anything.
- The follow-up series U.S.Avengers mentions it again, with the future Captain America saying only that it was "worse" than Zero Day, when pretty much every major hero died at Thanos's hands.
- Scrooge McDuck made many such references in comics by Carl Barks, which were intended as pure throwaway references to give the impression that Scrooge has lived a long, exciting life as an adventurer and businessman. Many years later, Don Rosa took many of Barks's offhand references and used them as the basis of The Life and Times of Scrooge McDuck.
- Deconstruction Fic Challenge of the Super Friends: The End has the Legion of Doom enter another universe. Cryptic references are given constantly to this world's past and how it got to be that way, but nothing is outright stated, leaving the reader's imagination to connect the dots. The characters are just as baffled as the reader.
- In the Doctor Who fanfic Gemini, one of Ax-Crazy Serial-Killer Killer Captain June Harper's signature trick-shots is based on a "Taska Venkman" series of spy movies.
- With Strings Attached is loaded with these, both overt and subtle. Examples include:
- The Idris' attic is filled with artifacts that don't quite belong there, notably a stack of books in several different languages.
- The Deep Gap. What created it?
- All the crumbling towns and cities of Baravada. Shag and Varx toss off a line about how the Dalns gods are somehow responsible for them, but don't elaborate.
- The Tayhil invasion. What exactly happened during that?
- The Wizards' University, where Grunnel once taught and where Brox is currently doing research.
- What About Witch Queen? has some, mostly used to expand the world. For example:
- Tampere Empire is mentioned a few times as the biggest country in the region and a neighbor to both Corona and Arendelle.
- There exists Far East. Tampere focuses on politics there and Southern Isles have ambassador there, but nothing else is ever said.
- Southernmost Lands, an apparent stand-in for America of Era of Discoveries, with Mayincatec names and kangaroos, where everyone can allegedly start a new life.
- Non-geographical examples include the Noodle Incident that caused Hauser to be Reassigned to Antarctica and hate Ferdinand, as well as some event in the past that caused Southern Isles to secede from Confederacy.
- In The Mansionverse, no one precisely knows where the Haunted Mansion itself came from, nor what happened to The Old Gods.
Films — Live-Action
- The Adventures of Buckaroo Banzai Across the 8th Dimension is littered with allusions to characters we never meet and adventures we never hear anything else about, artifacts left over from the writers' original plans for a multi-media franchise, which never panned out. A lot of the ones in the film are explained in the novelization of same, but it's been out of print for years and raises even more of its own, so...
- Blade Runner: "I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched C-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. ... Time to die."
- Pirates of the Caribbean:
- Jack Sparrow makes several non sequitur references to his past exploits (e.g., "And then they made me their chief.", "Clearly you've never been to Singapore.") that enrich his character. The sequels try to tie the movies together by creating plot points out of them.
- When we actually do get to Singapore we never find out exactly what Jack did to offend Sao Feng, so this trope appears again.
- Also, Elizabeth's speech on Black Sam's Spit: "But you're Captain Jack Sparrow. You vanished from under the eyes of seven agents of the East India Company. You sacked Nassau port without firing a shot. Are you the pirate I've read about or not?"
- A mook in Ronin asks Jean Reno's former spy "Don't I recognize you?" He replies "Vienna" and shoots him. It's not relevant to the plot at all.
- Star Wars:
- Upon its original release, A New Hope was a prime example of this, full of name-drops that have nothing to do with the plot but which combine to make the fictional world feel boundless and lived-in. References to the Imperial Senate, the Old Republic, "big Corellian ships" and the spice mines of Kessel are a few examples. Scenes that were cut in the original release, such as Han's confrontation with Jabba the Hutt, also make things like Greedo's confronting Han over something he did to wrong Jabba seem bigger. Every single throwaway line has been since filled in to ridiculous levels of detail by either the prequels or the Expanded Universe.
- Ironically the Expanded Universe has never introduced any ship to match Han's line about the "Imperial starcruisers" that are "big Corellian ships."
Lando: She's as safe now as she's ever likely to be. Don't worry about that.
Han: You know, that's almost exactly the same thing you said back on Boordii. That botched dolfrima run — remember? You said, 'It'll be fine; don't worry about it.'
Lando: Yes, but this time I mean it.
- More references include the Clone Wars, "that bounty hunter we ran into on Ord Mantell...," the Kessel Run, "many Bothans died...," Han and Lando's history, etc.
- Will and Ned from Unforgiven often talked about their old gang.
- The Way of the Gun makes a few references "what happened in Baltimore," some apparently shameful event in the OBGYN's past that has left him with limited opportunities.
- Escape from New York: The line "You flew the Gullfire over Leningrad, didn't you?" hints at Snake's past and a possible war with the Soviet Union. Also the fact that everyone thought he was dead for some reason.
- While Jupiter Ascending is actually pretty good at world-building with background references and a surprisingly interesting universe, one reference in particular feels cryptic. Caine, the part-wolf part-human super soldier, is said to have ripped the throat out of an Entitled, yet he doesn't remember the incident taking place and apparently was informed of its occurrence by his mentor, Stinger. The only indication that it actually happened is that he was court-martialed for the crime, and is no longer a skyjacker. Who the Entitled was, the reasons for it occurring, and why Caine is said to have done it in a fit of rage when we never see him acting out of rage at any point in the movie, is never expanded upon.
- The term "Double D-anniversary" in What Dreams May Come. Christy and Annie are repeatedly referring to this event without giving an explanation until towards the end when we flash back to the scene where this term was coined:
Christy: Today is kind of a D-Day. "D" for decision, I guess. About divorce.
Annie: That'd be two D's, wouldn't it?
Christy: I stand corrected.
- In Airplane!, neither Striker nor any of his fellow crewmates will ever forget that day over Macho Grande.
- Rollie from F/X: Murder by Illusion regularly drops names of movies he'd worked on when he or Andy re-purpose equipment from those films to foil the opposition (e.g. "smoke pots from Hellraisers").
- J. R. R. Tolkien was a master of World Building, working on his Middle-Earth world from about WW1 until his death. The Lord of the Rings is full of lovingly crafted and referred-to details, many of which are left unexplained, whose stories first got public with the posthumous publications of the earlier stories.
- One thing Tolkien knew from his studies as a linguist and English teacher is that some of the old myths recreate the Cryptic Background Reference effect entirely by accident, when the relevant poems or stories are lost — the medieval Finns probably had an explanation of what a Sampo (from The Kalevala) is, for example, but it didn't survive the Middle Ages.
- Then there are some things which never got elaborated on, even posthumously, like in The Hobbit when Bilbo makes reference to "the wild Were-worms in the Last Desert." Nothing remotely similar is ever even spoken of again.
- "Far, far below the deepest delvings of the Dwarves, the world is gnawed by nameless things."
- Half of fun of reading Tolkien is this. Go read The Silmarillion and go back and read The Lord of the Rings. Now revel in all the references most people didn't get the first time around. That part of the song Aragorn sings in The Fellowship of the Ring about Beren and Lúthien? Now you know the whole story. Bilbo's song about Eärendil that Aragorn seemed to find so cheeky to sing in Rivendell? It was about Elrond's father (and mother) who he hasn't seen in five thousand years and probably dredged up some bad memories about the ransacking of his home when he was a child by the sons of Fëanor. The list goes on.
- The Second Prophecy of Mandos, which describes what the end of the world will be like, is referenced (though not by name) in virtually all of the canonical stories of Middle-earth. However, the prophecy itself does not appear in canon — only in Tolkien's earlier drafts for The Silmarillion.
- H.P. Lovecraft is a prime example. His stories make repeated, throwaway references to fictional books and locales, but there's little evidence that the man himself had any unified vision in mind. His pals also did the same, throwing out cryptic Shout Outs to Lovecraft and each other's works. Enticed, the readers wanted more, and piecing together such references is part of the fun of the Cthulhu Mythos.
- Thursday Next:
- Lampshaded continually in the series in the form of Textual Sieves. Roughly every other time they're mentioned, someone asks what they do, and are told that no one knows, since they're so sparsely described. Thursday asks Miss Havisham, and in turn Thursday 5 asks Thursday how textual sieves work and the given explanation is "it's never properly explained."
- There's plenty of other examples, such as the "Boojumorial" of Jurisfiction agents lost in action ("Boojumed", or deleted), the views across the wilderness to other Great Libraries for other languages, the City of Adventure that is the Well of Lost Plots, previous disasters in the BookWorld (apparently, Titus Andronicus used be "a gentle comedy of manners", but increasingly bad behaviour by the characters turned it into the "the daftest, bloodiest play in all of Shakespeare"), and items in Thursday's TravelBook that haven't yet turned out to be Chekhovs Guns, such as String TM. There's even more examples in the Outworld, which to Thursday is the real world. Genetic engineering means they've resurrected the woolly mammoth, but they don't have ducks; Britain was invaded by the Nazis during World War II and comedy musician George "When I'm Cleaning Windows" Formby led the Resistance, later becoming President-For-Life; The People's Republic of Wales; riots over art styles and literature; the weirder parts of SpecOps, and so on.
- In the Mad Tea-Party scene from Alice's Adventures in Wonderland, The Mad Hatter proposes the riddle, "Why is a raven like a writing-desk?" Some time passes before Alice, the Hatter and the March Hare all admit that they can't find the answer. This did nothing to stop readers from persistently trying to find answers such as "Edgar Allan Poe wrote on both." Although Carroll himself eventually came up with the answer "Because it can produce a few notes, though they are very flat; and it is nevar put with the wrong end in front!" Or "They both have inky quills"
- Loyal Enemies has vampire kingdoms, which are alluded to a few times, and the islands, which are somewhere in Beloria, but we don't even learn in what direction.
- Stephen Brust's Dragaera books use this in massive amounts. Paarfi's novels are supposed to be historical fiction novels within the universe, so they assume that the reader is a Dragaeran who doesn't need additional explanations. Vlad sometimes seems to make the same assumption, but other times he explains common aspects of the world for the reader's benefit. Vlad will also make vague references to his various other misadventures outside of the scope of the current story without going into detail. Sometimes he says he doesn't want to digress, and other times he's simply cryptic. Some of these do get explained in future novels. Brust intentionally includes them as possible story hooks for future novels without planning on where they'll go.
- The Harry Potter books sometimes play this straight and sometimes use it to disguise a Chekhov's Gun.
- In the Sherlock Holmes stories, Watson is famous for this, often referring to other cases, such as the one involving "the giant rat of Sumatra, for which the world is not yet prepared". Some of these became stories in their own right (though usually not from Doyle's pen), but most remain unexplained.
- Used masterfully well in Ulysses Silva's novel Solstice. There is exactly one incident where things are properly explained by the main character (even then, it's mostly clarification on things you've picked up). Everything else is left for the reader to figure out. And quite often, everything you thought you'd figured out turns out to be completely wrong, leading to many an Epileptic Tree until the very end.
- Much like the Sherlock Holmes example, the Nero Wolfe series by Rex Stout begins on terms of false familiarity, and vaguely references past cases that are never fully explained.
- Neverwhere is full of this. Particularly the Big Bad's motivation for sinking Atlantis. All we get is him shouting "THEY DESERVED IT!" Neil Gaiman's work has tons of this, but Neverwhere and Stardust are particularly big examples.
- In Michael Ende's The Neverending Story, many vague allusions are made to the further adventures of secondary characters, always accompanied by the phrase, "But that is another story, and will be told another time." Needless to say, said stories have never been told.
- Actually plot-significant, and gives the book its title. In the ending, Bastian is told he can't leave until every storyline he started up is finished. But given the rate uncompleted plots have been created (several story hooks get created for every one he finishes) he'd never be done. Atreyu saves him by taking on the task on his behalf. The movies leave this out, resulting in an Artifact Title.
- The Hitchhiker's Guide to the Galaxy is littered with these, with allusions to far-off planets and some of their inhabitants that are never explored in-depth. For instance, Maximegalon is apparently a planet with a very rich academic history, although it's never visited; neither is Blagulon Kappa, a world mentioned off-handedly several times but about which even less is explicitly stated. On the character side of things, Oolon Colluphid is apparently a very prestigious writer and an acquaintance of Zaphod Beeblebrox's (as of the sixth book), and some of his books have been named, but he's never personally encountered. The same goes for Eccentrica Gallumbits, the triple-breasted whore of Eroticon VI, and ex-president Yooden Vranx, who would have been part of the first story arc, but the author wound up not going there. What's really interesting is that the many of the stars and systems he mentions are real, like Sirius. This amuses people with arbitrary knowledge of stars.
- There's also a bunch of almost-correct ones. There is no real-life planet called Ursa Minor Beta, but there is a star called Beta Ursae Minoris.
- Used in the Old Kingdom books by Garth Nix, and not overused, either. He's mentioned in interviews that he's not really into world-building — he just makes everything up as he goes along.
- Simon R Green often uses this trope in the Nightside series.
- Raymond E. Feist's Riftwar cycle, there is a place called Roldem in the east of Midkemia. It is mentioned in a few of the books, and included in every map of the world, however over the course of more than 20 books, it is not visited at all. In fact, most of the information on Roldem comes from a single e-mail written in 1998.
- In the Codex Alera stories, there are several mentions of a group called "The Children of the Sun" who were, it seems, wiped out by the Alerans relatively recently (historically speaking) and, as a last action, did something, somewhere, for some reason and now there's the Feverthorn Jungle in the middle of the continent, that no one can enter for reasons which are unexplained. Though we get a rough idea of where it is (middle southeast of the continent according to the map in First Lord's Fury) what makes the jungle impenetrable (even to the Vord) is unexplained. The Alerans idly speculate that if they could figure out what the Children did, they might be able to turn it against the Vord.
- Also All There in the Manual, as Butcher explained it on the website. They're another sentient race (of plant-people, with Woodcrafting-like powers), who are now all dead, wiped out by the Roman legions shortly after they arrived on Alera (and hence before they had developed significant furycrafting). Of all the sentient races that have appeared on Alera, only the toughest survive the competition.
- Part of the charm of the early books of Chronicles of the Kencyrath is that the main character is a member of a race with ten thousand years of history, but our glimpses of this history is as through a glass darkly because the main character already knows her history and doesn't feel the need to monologue about it. The later books have filled in many of the references, but far from all of them.
- The story of Princess Nell in Neal Stephenson's The Diamond Age starts out like this, and Nell and the Primer spend the next decade or so expanding the references.
- George R.R. Martin has stated that not all locations on the map of A Song of Ice and Fire will be visited in the story. Consider the fact that no viewpoint character has yet visited (during the story, that is) the Lannisters' home Casterly Rock, or the Basilisk Isles that show up on the map of (part of) the Eastern Continent.
- The series is full cryptic background references to various events (the tragedy at Summerhall, the Tower of Joy, "The Rains of Castamere," the Blackfyre rebellion, the Ninepenny Kings, the Doom of Valyria, etc). As the series moves on, some of them have been at least partially explained.
- Alien characters in Animorphs often allude to various other species or situations that have nothing to do with the plot:
- For example, early books would sometimes list random species the Yeerks had supposedly enslaved, though practically none of them are seen except for Hork-Bajir, Taxxons and Gedds.
- There's also a whole subplot happening off-scene with a planet called Anati: apparently the Yeerks knew very little about it (including whether or not it was inhabited) and sent Visser One to conquer it, but she wound up failing for some unknown reason.
- "The Five", the mysterious race responsible for hunting the Venber to extinction. Ax doesn't know where they came from or why they called themselves that, but they have since also vanished, possibly due to the Andalites of old giving them a taste of their own medicine.
- At the end of book 41, the Bad Future Jake was experiencing turns out to be a psychological test conducted by an unknown being, for no obvious reason but curiosity. We never find out who was running it.
- Crayak, the closest thing the series has to Satan, was evicted from his galaxy of origin by an even more powerful being.
- Following the tradition of the films, the Star Wars Expanded Universe make references of their own, some of them mentioned or expanded on by others, some of them never mentioned again. It gets downright fractal at times. Try hitting Random Page on Wookieepedia and see how far you can get before finding an article with one line of description and one or two appearances.
- Often used in Discworld, with throwaway references to things like the politics of the Guild of Engravers (although that one eventually became The Truth), or the various notes on Sam Vimes's desk that he's too busy with the main story to deal with, creating the feel that Ankh-Morpork keeps running even when there isn't a story happening.
- In the beginning of The Dark Tower, the third-person narrator often makes references to historical events and figures, such as the fall of Gilead and John Farson, as well as important characters in the gunslinger's past. Many of these are clarified later in the series, further expanding the previously sparse world.
- The Stormlight Archive has lots of these, references made by characters to things that happened in their pasts, references to the history of the world etc. Given that only the first book of a ten book series has been released, and that Brandon Sanderson loves to collect loads and loads of Chekhov's guns it's highly likely that a lot of them are just waiting to go off.
- The Wheel of Time novels are full of references to epic historical events and heroes, and the landscape is littered with ruins and relics of bygone ages. Some of it gets expanded on and turns out to be important to the backstory, but a lot is just hinted at to give the impression that the setting is old and didn't just sit there doing nothing until the main characters arrived.
- Even happens in-universe, with Birgitte and Mat (after he starts gaining access to the memories of his past life). Being ancient characters, they have witnessed events that happened THOUSANDS of years prior and have been losts to the mists of time, so nobody around them has any idea what they're talking about when they start spouting off references.
- And because time in the setting is cyclical, many of the references are in fact to actual historical events in our time, but with the details garbled by the passage of the ages. Many of the oldest songs and stories will actually be surprisingly familiar to readers.
- Mercedes Lackey's Heralds of Valdemar novels have a handy store of ancient history at which to hint. Some characters (Vanyel, Lavan Firestorm) have had their own books, but she claims "Windrider" and "Sun and Shadow" likely will not, since they work better as distant legends.
- The Dresden Files contain a fair amount of them, such as the reasons for some wizards not showing up to a White Council meeting in Chicago including "He got real married", "Living under a polar ice cap", and "Pyramid Sitting".
- In a case that ultimately ended up a subversion; in the first book Harry mentions that Santa Claus is real, and implies he's terrifying. Fast forward fourteen books, and we finally meet him in Cold Days, and get a good idea of why Harry would have been scared of him in the first book.
- Sandy Mitchell's Ciaphas Cain books have loads, some of which get stories (a reference to hunting Tyranids on a hulk, now released as The Emperor's Finest), others are not (yet) fleshed out (his encounter with a Dark Eldar wytch, and time spent on a Tau world, for instance).
- In the Super Mario Bros. Nintendo Adventure Book Pipe Down!, Princess Toadstool mentions that in the past (around the time of her ancestors) there were things far worse and more powerful than the Koopa Kingdom, but no elaboration is offered as to what she means by that.
- The Mechwarrior Dark Age novels (based on the BattleTech game world) made references to events that had occurred in the 65-year Time Skip since the last published BattleTech novel. The result was a lot of terms used in general discussion that had no explanation - The Jihad, the Ruins of Gabriel, Apollyon, the Master and so forth. Since then, new BattleTech fiction has begun to explain some of this.
- Loads. The names of cultures and warlords are dropped without context, only to be explained a dozen chapters later. Since there's lots of Theme Naming and Shout Outs, the audience has some clues to figure out what the names refer to before they appear on screen.
- The Dagonites get referenced every few chapters for hundreds of chapters, with no explanation. Even when Dagonite characters show up on screen, the other characters just note that they don't look as weird as they expected, and move on.
- Space colonies are referenced as well. A refugee from a minor mutiny on the Chinese Shaohao station crash-lands at one point, and later it's mentioned that the Soviet Tsiolkovsky Station is the communications hub for the colonies. Ceres gets a few mentions (it's implied to be a factory colony), and someone says that a character is from "Lemuria, on Mars."
- The fall of Eden is mentioned more than once as an important part of the city's past, but no context is given.
- With the Monster Blood Tattoo series, D. M. Cornish not only strives to make the Half-Continent feel lived in with side comments and throwaway lines, but he has so many side characters who appear and reappear within Rossamund's narrative that it leaves readers thirsty for all the potential other stories that could be told. There is, after all, a reason why the glossaries in the back of the books can be a third of the physical book.
- Used fairly frequently in Herbie Brennan's The Faerie Wars Chronicles. Since most of the series is set in a fantasy realm with only two non-native characters present, references to simbala parlours, power outrages, border Redcaps, or The Reindeer King of Crippenmas are pretty commonplace. Some of these are given explanations in the glossaries, and a few end up connecting to the plots of later books, but many are left entirely unexplained.
- The Gods Themselves provides no detail on an event that killed about 4 billion people: "Just about the time the Lunar colony was being established, Earth went through the Great Crisis. I don't have to tell you about that."
- In the NaNoWriMo novel And Then There Were Monsters, some of the monsters mentioned in the text are explained in Father Mallern's journals. Most are not. Dire cattle, for example, and referenced a few times, but never seen, and in the end all we know is that the only similarity they have with normal cattle is that they still have four legs.
- Hannu Rajaniemi's The Quantum Thief features many references to cataclysmic events that shaped the world of the novel, but remain a mystery to the reader, and sometimes even to the characters due to lost historical records and memory manipulation. These include the Collapse that caused most people to abandon Earth, the Cry of Wrath, the Spike which somehow destroyed Jupiter, and the Protocol War. Some get elaborated in the later books and even become major plot points, while others remain a mystery.
- C.S. Lewis's The Chronicles of Narnia has a few of these. For instance, in The Voyage of the Dawn Treader, the children meet a magician, who is later revealed to be personified star who was sent to earth as a punishment. On being asked what possible crime a star could commit, they are simply told: "it is not for you, a Son of Adam, to know what faults a star can commit." The reference gets even more cryptic when Eustace comments that in their world stars are balls of flaming gas and is told that even in our world, that is not what stars are, but only what they are made of.
- Charlie and the Chocolate Factory has Mr. Willy Wonka noting that Loompaland, the homeland of the Oompa-Loompas — and a country none of the other characters have heard of — is a Hungry Jungle full of "hornswogglers and snozzwangers and those terrible wicked whangdoodles" without explaining what exactly those beasts are (besides very hungry). This isn't surprising, as Mr. Wonka himself has a never-explained Mysterious Past and is Inexplicably Awesome. (For one thing, between the original novel and its sequel, he's apparently managed to travel the world without being recognized for years, and has knowledge of other planets and alien races. Also, the 2013 stage musical plays this concept for laughs with throwaway lines that reveal that he used to go to raves.)
- Two examples from Distortionverse:
- the Tryadine Effect case which was solved by Veckert before the events told in Chapter 1 - La Notte che Cammina and resulted in the opening of the dome of St. Patrick SHIELD is never explained in details — only hinted at;
- the bombardment of Moscow mentioned by Egon Kramers in Sabbie.
- Gary Seven is references events and races in The Eugenics Wars when Roberta asks him to justify whatever their mission is - some of which the audience has heard of, some of which were just made up. Discussed when Roberta complains that she's never heard of these events or races and can hardly check up on them.
- World War Z is in love with this trope, with casual mentions of numerous events during the Zombie War that never gets explained in-depth.
- Literature/Worm has many cryptic references, some of which receive later explanations or story arcs. The Sleeper is the most prominent example that remains cryptic, an S-class threat whose presence causes an entire dimension to be written off for reasons that are so obvious to everyone that the reader gets no explanation.
- "The Tamarisk Hunter": The events surrounding Lake Havasu City are referred to in-story, but beyond involving water and possibly the destruction of a water plant, it's not clear what they were.
- Game of Thrones: Events surrounding Lyanna's abduction and her eventual death remained a mystery until late in the series. Some of the events transformed into foreshadowing after the 6th season finale revealed she died giving birth to Rhaegar's son, whom her brother adopted and renamed Jon Snow. In-universe, the abduction remains a cryptic reference even after the audience (and Bran and Sam) get a complete explanation in season 7.
- In Stargate SG-1, one of the four great races is the Furlings, who are never shown in 10 years of episodes (though a parody in episode 200 shows them as small furry creatures, looking somewhat like Ewoks). The non-appearance of the Furlings has become something of a Running Gag, since the parody starts with surprise to even meet them, and ends with the Furling homeworld being destroyed.
- In addition to the character backstories seen in flashbacks, Lost has included a number of throwaway references that have captured fan imaginations, including Sawyer's "Tampa job" and Sayid's Basra incident.
- In Doctor Who, all bets are off. The Doctor will routinely spout off about unexplained spatial phenomena, utterly bizarre alien cultures and references to the Last Great Time War and too many other things to even think about listing. These are often expanded on in books or audio dramas, and occasionally later in the show itself.
- Stories with the Third Doctor (and occasionally others) often make mention of an unnamed "monk" or "hermit" the Doctor knew long ago. The audience finally met the monk in the Third Doctor's final story. Whether the "hermit" was the same person has been the subject of much debate among fans.
- It's virtually guaranteed that whenever the Doctor meets the Master, they will talk about their childhood and various parts of their own backstories and identities, which of course will never be explained because of how important the mystery behind them (as well as the Time Lords and Gallifrey as a whole) is to both characters.
- Characters other than the Doctor are known to do this, too. For example, Captain Jack Harkness of Torchwood fame. This mostly has to do with various sexual exploits, but he does mention actual bizarre past experiences. Random side-characters can do this too, usually to the Doctor or one of his companions, with the assumption that they're from the same period/place, and know what they mean.
- We know about Torchwood 1 (from the Doctor Who episodes "Army of Ghosts" and "Doomsday") and Torchwood 3 (from Torchwood). But the mysterious disappearance of Torchwood 4, and why Torchwood 2 is one guy, called Archie, above a bank in Glasgow, ("A very strange man") will probably never be revealed.
- Unintentionally done in the TV series adaptation of The Dresden Files, where things that are explained in the books are referenced, but are never explained in the series. It is possible they would have been, had the show not been canceled after a season.
- How I Met Your Mother: There was much speculation as to the origins of the goat in Ted's apartment, which is mentioned in season three but abruptly dismissed with "oh wait, that was on my thirty-FIRST birthday". Fans had a whole season to wonder, but the actual explanation was, perhaps inevitably, a bit of a letdown.
- The title itself refers to How Ted Met the Mother of His Children. It took until the end of season 8 before we saw her face.
- The constantly expanding Star Trek universe is replete with this one and usually two or three are generated per episode.
- A common theme in Star Trek: The Original Series and early Star Trek: The Next Generation is having a character list one or two examples from real-world history and adding a fictional example from the setting that is implied to be similar by association but is never elaborated upon or referenced again.
- The other most common thing are events that occurred in the fictional gaps of time between the various eras (Approximately 100 years elapsed between Enterprise and The Original Series, 15ish years for TOS and The Wrath of Khan (The Motion Picture being close-ish to TOS' present), and 80ish for The Original Series and The Next Generation. Significant things happened during those periods that are frequently referred to, but almost never shown on screen ("What happened to the Enterprise-B?" and the Earth-Romulan War being some of the big ones.) The Expanded Universe naturally latches onto these things like crazy.
- In the Star Trek: Voyager episode "The Omega Directive" it's mentioned that the titular directive was established after an accident with the Omega Particles happened to Federation scientists in 2269. The fact that 2269 is in the middle of Kirk's five year mission, and this neither references an episode of the original series, nor mentions any involvement from the Enterprise (but doesn't discount it) makes it all the more cryptic.
- They Double Subverted this trope in regards to a specific alien race. Since TNG, there has been mention of an alien race called the Breen, though all that was known about them is that their homeworld is very cold. They finally show up in DS9, but in full body environmental suits that completely disguises their appearance, and nothing at all about their society is revealed. A throwaway line in DS9 suggests that they are extremely secretive by nature, so that not even the people in the shows know much about them.
- Star Trek: Deep Space Nine referred in a couple of episodes ("The Adversary" and "Home Front") to a race called the Tzenkethi. All we learned was that their leader was called the Autarch, and that they'd previously fought a war with the Federation during which Ben Sisko served as first officer of the USS Okinawa under then-Captain Leyton. The EU used this as a jumping-off point for several novels, including making them a major player in the Typhon Pact following the Dominion War.
- Leverage has several of these, such as the named cons that we never see the team run, like the "London Spank," the "Genevan Paso Doble" and the "Apple Pie," which is a "Cherry Pie" but with lifeguards. Also, there's what Nate did at the Russian border. Word of God says that he may have technically hijacked a train, but that hasn't been mentioned on the show and likely never will be.
- We've also seen the team coming back from jobs - one in Mexico where Parker picked up a lot of pinatas, and one in the Caribbean that went wrong in several different ways - without hearing much about what those jobs actually were.
- Babylon 5 subverted this trope quite often, given that it was all plotted out in advance. For instance, the fates of all the previous Babylon stations seemed to be a case of simple world-building, to stress how dangerous the universe was. But then we learned what happened to them: Three destroyed, one vanished. Then the vanished one shows up again, having been Unstuck in Time. Then it gets even deeper, when it's revealed that Sinclair, The Captain in the first season, was in fact that Minbari prophet Valen, after he'd traveled back in time to provide the Minbari with the space station they desperately needed to win a war, which also helps to explain the random weirdness of Delenn becoming half-human. Other factors, like the unstable politics of Mars, also come up again in later seasons to be fleshed out. Other things, however, were left to the imagination. Such as what it was about Vree eating habits that disgusted G'Kar so much that he considered sitting next to them to be an insult to his entire government.
- Merlin occasionally references the Ancient Kings and the High Priestesses, who were apparently embroiled in some sort of war for supremacy before Uther came to power.
- Buffy the Vampire Slayer did this sometimes. For example in "The Prom", Wesley mentioned the "Machash Wars".
- Burn Notice does this a lot by mentioning various ops the main characters have done before the start of the series.
- The Wire shows the city of Baltimore had its own mythology in its criminal underworld.
- The song "Red Barchetta," from the Rush album Moving Pictures, takes place in an unspecified dystopian future and relies heavily on this trope to paint an impression of the setting in the song's limited timeframe. An example:
My uncle has a country place that no one knows aboutHe says it used to be a farm before the Motor LawAnd on Sundays I elude the Eyes and hop a turbine freightTo far outside the Wire, where my white-haired uncle waits.
- The original short story that inspired the lyrics is a bit more descriptive of the setting, but still has examples.
- Phil Collins made up the lyrics to "In the Air Tonight" while recording, admitting that they have no specific meaning but their ominous tone was inspired by his undergoing a bitter divorce from his first wife. Attempts by people to read into the lyrics have spawned Urban Legends, including the more infamous one that suggested the song was about Collins witnessing a friend of his who drowned because somebody else refused to help, and how later Collins saw the same person at one of his concerts, directed a spotlight towards them and sang the song, driving the person to suicide.
- Magic: The Gathering uses this a lot in their Flavor Texts. Many of the early ones were given explanations later, but not all - for example, we still don't know whose uncle Uncle Istvan is supposed to be.
- Unknown Armies. Even if you manage to read through every single supplement and piece together as much as you can, there are still a lot of holes. But, since the game's major theme is a world of mystical insanity seething just below the facade of normalcy, it's generally agreed that it just wouldn't make sense if everything made sense.
- The current incarnation of the Necrons in Warhammer 40,000 was inspired largely by a throwaway line by Rick Priestley about "the quiescent perils of the C'tan" which "lay beyond the Gates of Varl". References were quietly worked into the game over the years in the form of the C'tan phase sword and phase knife, until the release of the first Necron codex where the C'tan were finally revealed as the "gods" of the Necrons, indescribably ancient and evil monsters which feed on suns.
- There are also the two "missing" Space Marine Primarchs and their Legions. Every mention of the twenty Primarchs lists numbers II and XI as "All records deleted", and EU works have consistently refused to give any detail about who they were or what happened to them.
- The Horus Heresy series of novels and audiobooks have touched on the subject obliquely, ranging from intimations of an accident at the gestation stage, to something so shameful and terrible that the Imperium refuses to acknowledge them, even when daemon-worshiping, civilian massacring, backstabbing psychopathic unrepentant bastards are still listed in the records (admittedly, usually with the note "Explode planet on rumour of presence", but still). The exact details have never been revealed and are unlikely to be either, this is lampshaded by characters telling each other not to even think about discussing the details.
- The closest we get is a throw-away line saying that the Space Wolves had previously been ordered to attack a Space Marine Legion.
- There are also the two "missing" Space Marine Primarchs and their Legions. Every mention of the twenty Primarchs lists numbers II and XI as "All records deleted", and EU works have consistently refused to give any detail about who they were or what happened to them.
- Now that the game numbers something like 50 books, there's very little in Rifts that was mentioned in the first book that hasn't gotten a description by now. One of the biggest examples was the Republicans, which was an off-hand mention in the first book about a technological society living in the ruins of Washington, D.C. It was the subject of several unofficial Sourcebooks (called Netbooks) until they were finally described in the Expanded Edition of the original Sourcebook. There are still a few things here and there that have gotten mentioned but still not shown. The most notorious is the permanently-open Rift in Calgary, Alberta, and the monster kingdom that's developed there, as well as others like the Blood Druids of France.
- Psionics: The Next Stage in Human Evolution: Rose Klein (AKA Mama Bear) gets one in Tomorrow’s Starlight. Its never explained what the “Albuquerque Incident” was, but it was apparently enough to get her a maximum threat rating from The Shop.
- This happens once a game in the Summon Night: Swordcraft Story games: random NPCs come into the scene and reference something that would make sense as part of a longer plot but which you don't know about. ("I would gladly fight to the death to follow the last orders of Master Shinrai!" ...Master who?) How much of this is the result of this actually being a spin-off series of a larger plot that never made it outside Japan isn't immediately obvious to English-speaking players.
- Street Fighter II contained the mysterious line "You must defeat Sheng Long to stand a chance," prompting much debate on just who "Sheng Long" was and a rumor that he was an unlockable character. It was eventually explained that the name actually just referred to one of Ryu's attacks, not another person. But still...
- Then there's Bison/Vega crowing about how "The Ancient One" couldn't face him. And Fei Long dedicating his art to "the master and his son" (actually a reference to Bruce Lee, Fei Long's expy source). And those three college students who inspired Sakura to take up fighting. And anything at all involving Gill. That's not even touching on the whole sordid tale of how Charlie Nash's death happened, or for that matter, where it happened, which has so many possible explanations by now, it qualifies as a Multiple-Choice Past.
- Undoubtedly the biggest issue involving said Sheng Long, the canon ending to the first tournament. Other than the basic fact of Ryu hitting Sagat really, really hard, we're never going to know for sure what actually happened. The most likely scenario, in fact, involves Ryu connecting with Sagat's chin (the usual one hit KO location for MMA); any blow to the chest forceful enough to put away a brawny heavyweight would've left a much larger scar than what Sagat's currently sporting.
- Kingdom Hearts enjoys this quite a bit. The meaning of the phrase that started the series, "You are the one who will open the door to light" has still not been fully explained. In the first game, Sora closes the Door to Darkness; in the second, he finds Kairi's letter, which does open a path back home, but as he's not the one opening it technically, it's unknown just what the phrase means.
- Super Robot Wars lives on this trope - Throwaway references became major plot elements in later games - such as Lemon's last name, and referring to a 'Beowulf' who piloted a 'Gespenst Mk. III' (Alt Eisen) - obscure references to the previous game, where the protagonist's theme called was 'Steel Beowulf' and his unit was revealed to have been a modified Gespenst Mk. I considered for mass production. And many, many more.
- Mischief Makers treats all the characters as already established, and new characters are often brought in with the assumption that they've had encounters with main character Marina in the past.
- Cave Story. There are references to shared histories between characters, and to a war ten years ago with armies of robots from "the surface" attacking the Island, and to three bearers of the Demon Crown prior to the Doctor. There's just enough information to construct a vague timeline for the backstory, but it's obvious that there's more to the history than what we're told. When asked for further information about the game's world, the writer has said that he himself doesn't know.
- Sid Meier’s Alpha Centauri includes many fictional quotes from the game's characters and other people in the game's world. These as well as a handful of other game elements are the only inside look we have into what life on Planet is really like (unless you read the novelizations, anyway). Many details are left to the imagination, such as, "What exactly is 'nerve stapling', anyway?" Somehow, it works.
- In Tsukihime, during the final encounter with Nrvnqsr, he and Arcueid have a conversation on things that you don't learn until much later in the game, or in supplemental materials. This is intensified by the use of code-like terms, such as referring to Roa as the "Serpent of Akasha".
- From both Left 4 Dead games, the only parts of the story that are completely laid out for you are from the single 4-chapter comic ("The Sacrifice"), and the short character bios that each of the Survivors get (neither of which are found in-game). The rest of the plot that's given to you will only be through random (often campaign-specific) character dialogue, about 99% of which isn't even guaranteed to trigger (usually requiring multiple play-throughs if you want to catch everything), or occasionally from significant pieces of the map, but most of all from the writings on the walls of different saferooms (and occasionally elsewhere) of other people who have passed through that area, describing bits of their experiences as messages to others, agreement or disagreement with what the military is/was doing, just how bad CEDA failed, how fast somebody changes into a zombie after being infected, and so forth, but not even those people are in 100% consensus about whatever's been going on, and nobody really has any idea what even started the whole thing. We might get some answers eventually, but given Valve's reputation for making third installments, it's probably not going to be any time soon.
- Team Fortress 2 has this to an extent. It began with the Excuse Plot of two rival corporations hiring mercenaries to fight over seemingly trivial objectives. Each mercenary has a distinct and interesting personality, but virtually no Back Story is given and they didn't even have any real names. Since the release, more of the history leading up to the game has been revealed, and additional bits about some of the classes have come forward.
- Potentially, the increase in backstory has only increased this trope. Why does the Announcer control both sides, pitting against each other for no apparent reason? What are her connections to Saxton Hale and the Redmond and Blutarch families? Why is friendship such an alien concept to her? What will the Engie do with all that secret deposits of Australium? How did the Soldier get a magician as a roommate? (All this only appears in the addition material. If you're content to run around reducing other players to bloody chunks it won't bother you. After all, reducing each other to bloody chunks is the point of the game.)
- It seems that Valve is fond of this trope. The Half-Life series is almost entirely built out of it. What were the various departments at Black Mesa researching? What do those vast Combine machines actually do? How did those corpses end up where they are? Who was the Rat Man? Who was Lazlo? The vast majority of the story is told by implication only.
- The "Rat Man" from Portal was later explained in the Lab Rat comic that was released alongside Portal 2.
- BlazBlue has six legendary heroes. Hakumen is playable, Jubei and Valkenhayn Hellsing show up as NPCs and the rest are shown only as silhouettes until Continuum Shift. It adds Terumi Yuuki to the playable list, adds Platinum (one of the three souls in her body being that of Six Heroes member Trinity Glassfield) to the NPC list and reveals that Nine is dead. Valkenhayn and Platinum later became playable through DLC and expansions, and the silent villain Phantom is heavily implied to be a brainwashed Nine.
- Fable I and Fable II gives us all kinds of elaborate references to places you never go, ancient tribes and cults, and legendary heroes, none of which are ever seen.
- The driving force behind The King of Fighters, Orochi, qualifies. The only things we know for certain are 1. it involves a horribly evil destructive power, 2. the clan is absolutely fanatical and will stop at nothing to raise their god, 3. the Kusanagi, Yagami, and Kagura clans were the ancestral foes of Orochi, 4. but the Yagami betrayed the alliance, causing their flames to turn purple. Everything else is a confused mishmash... some artifacts we never actually see (until Ash Crimson starts pilfering the current clan members of their powers in the 2003-XIII arc), "maidens" who may or may not have been slaughtered, Kyo getting preferential treatment causing Iori to go all emo or something, a bunch of sealing and unsealing attempts, "battle energy", earth worship and "returning all to nothing", Rugal of all people chosen as a guinea pig, self-destruction, betrayals, counter-betrayals, etc., etc. Worst of all are the numerous plot points and outright sequel hooks that are flat-out dropped, such as a heavily-implied rift between Rose and Adelheid at the end of XI.
- It doesn't even end there. KOF mythos designates Orochi as "Gaia's Will"; it's not only the progeny of the earth mother of Greek myth (bizarrely enough), but her self-appointed guardian. Gaia herself has yet to directly appear in any capacity and is only mentioned in regards to her familial ties with Orochi and her creation of humanity, assuming she's mentioned at all. This begs the questions of where exactly is Gaia in the present, why did she create a being so fanatical in its duty to her that it vowed to destroy humanity (the very beings Gaia herself brought to life), and why is she practically non-existent not only in the face of her child's actions, but when dealing with earthly matters as a whole. More headscratching ensues if you take into account the greater SNK universe; one of the tournament regulars is the reincarnation/descendant of Gaia's great-granddaughter.
- Those from the Past's goal to obtain the power of Orochi by breaking its seal (yet again) comes across as this, as it's never clearly spelled out during the Tales of Ash what their leader Saiki wants to do with it. Not even in XIII, the climax of the saga wherein said leader makes a formal appearance and all of his scheming comes to fruition. Side materials reveal that the group is more or less the Western European equivalent of the Orochi clan and Saiki needs Orochi to power an artifact known as the Gate (which does appear in XIII) so he can travel back in time and change the flow of history so as to prevent the cult from suffering a horrible loss to their human adversaries (presumably Elisabeth's ancestors, thus explaining her personal vendetta against them and the repeated, equally cryptic mentions of her and Ash's "mission"). Sadly, little of this is explicitly mentioned in the game proper, and Saiki's shady, self-serving nature (complete with the implication that said explanation doesn't hold water) opens up grounds for further discussion.
- If there's one plot point in KOF that adheres to this concept more than anything else, it is—without a doubt—the Dragon Spirit. That subplot first reared its head back in KOF '99, with Kensou and Bao shown to be vessels for an otherworldly power coveted by the mysterious Ron (former leader of the Hizoku clan of assassins and a former member of NESTS, the villainous cartel of which KOF's third Story Arc centers on). Fast forward to XI and XIII and all we know is that Kensou has apparently mastered its powers (much to Ron's approval) and Ron has unspecified ties to Those from the Past (as Saiki alludes to Ron having warned him of Kensou in their pre-boss fight dialogue). We know nothing of the Dragon Spirit's origins or why Ron has his sights on it, although it can be inferred that this has something to do with Ron's betrayal of his clan. This is mainly an effect of the plotline mostly being put on hold in lieu of Those from the Past's machinations; with several Hizoku members being introduced to the cast since 2000 (including Ron's son Duo Lon, a semi-important supporting character from 2003 onward) and the Tales of Ash having come to a close with XIII, it's possible the next arc will finally revisit these story elements and elevate the ever-elusive Ron to main villain status.
- Touhou is filled with this trope. It ranges from important things like the Great Suwa War, Yukari's (first) invasion of the moon, and the sealing of Gensoukyou within the Hakurei Barrier, to miniscule details like Marisa's relationship with her father, the dispersal of the oni, and Rumia's ribbon. Add some Hufflepuff Houses and rampant Shrug of God, and the result is an entire series that is prime Canon Fodder.
- Silent Hill is another prime Canon Fodder series, as this trope tends to be the only source of available information. With one exception (Walter Sullivan, the main enemy in Silent Hill 4, was originally mentioned in a newspaper article in Silent Hill 2) none of them are explored or elaborated upon, and in the case of some this is probably for the best.
- Guild Wars has a few, though many of them ended up being explored in the Bonus Mission Pack.
- The Saboteur: What is the trouble that made Sean unable to return to Ireland? Who are the enemies he made there? What did Sean's father do there exactly? Where did Sean learn to use explosives? What was Sean doing in Budapest when he met Skylar? It's possible that the time period immediately before the literal "Troubles" in Ireland is referenced, and this would also explain how he learned to use explosives.
- Final Fantasy VIII does it occasionally, most notably with the sorceresses. For example, "Great Hyne" is mentioned as their progenitor and source of their powers, but you never learn who exactly that was, save for some legends told by NPC you're likely to miss.
- The Elder Scrolls series has thousands of years of backstory material that is only hinted at in the games, either through dialogue with various characters or in the many in-game books.
- Golden Sun games have a lot of this kind of information that you can gather from the various NPCs or furniture in the various towns, regarding the political and economic situations of your surroundings, gossip about local leaders, what the cuisine and culture are like in each place (in some places extending to religious beliefs), optional content you can explore, and once in a while some obscure lore tangentially related to the plot.
- Dark Dawn takes this a whole step further with the major characters themselves discussing some stuff in relatively major cutscenes that isn't at all involved in the plot of the game, like the three races of the Precursors, the modern geography and political unrest around Morgal and Bilibin, and Kraden's messenger pigeons. Fans were annoyed that this cut into plot and character development, which were less consistent than in the previous two games.
- Dragon Age: Origins has a lot of background material that isn't wholly relevant to the games' plot. Moreso in the sequel since the game takes place on a more personal level. Some particularly interesting bits of background are that the Primeval Thaig was apparently part of an ancient dwarven civilization predating the Deep Roads, which had temples and worshiped gods (and that the Primeval Thaig was ruled by a "dwarf so foul the Stone rejected him" and covered in evil red lyrium that drives people insane), that at least one Eluvian leads to "another place - beyond this world, beyond the Fade", that Flemeth is, at least according to Morrigan, something other than merely a mage or an abomination, and that the qunari must have arrived in Thedas (the continent where the games are set) from somewhere because they only showed up three hundred years ago, but no one knows where they came from.
- More subtly, there is the whole Codex business: in theory, it should offer exhaustive explanations and backstories of in-game events, items, and characters. However, in practice, one cryptic reference explanation contains three more references that don't get explained.
- The Warden can do this during Witch Hunt, only vaguely hinting to their new companions their precise relationship and reasons for searching for the Witch of the Wilds. Particularly noticable if Morrigan was romanced, where Ariane eventually comes to realise that the Wardens cryptic statement that "She has my child" didn't mean that Morrigan had kidnapped their child as she'd assumed, but actually because Morrigan was the mother of their child. Furthermore, she later figures out the nature of their relationship, asking the Warden if they are aware they subconsciously play with the ring on their finger when they think no-one is looking. After the Warden explains it's part of a pair shared with Morrigan, Ariane is genuinely amused when they fervently deny that this means they're married.
- Xenogears. A lot of the backstory involving dead civilizations and their predecessors from space but you only know (sparse) details from supplementary materials. Squaresoft was hoping to make sequels based on this information.
- Thief II: The Metal Age During the missions, you occasionally hear and read references to "the Baron", who's absence has allowed Sheriff Truart to assert his dominance over the city. No detail is given about who the Baron is or why he is absent, but this little detail creates the feeling that the game is set in a small corner of a much larger world.
- Demon's Souls, the Dark Souls series, and Bloodborne, like Valve's games described above, almost entirely bereft of traditional exposition, and the story of each game must largely be pieced together and inferred from item descriptions, level design, and the like. There are occasional characters better informed than the Player Character who will provide some precious information, but they generally prove untrustworthy.
- Hidetaka Miyazaki claims the inspiration for this style of storytelling came from him attempting to read Western fantasy novels as a teen despite having a limited grasp of English: he could only understand certain passages, many of which referred to objects or events described in passages he couldn't read, thus turning explained plot points into this trope.
- Far Cry 3:
- The casino chips you find in loot are described as being from "the Jeni Soleil Casino Cruise heist." This is not explained any further.
- Privateers will sometimes say "At least I'm not on that island with the dinosaurs." NB: in January 2015, Ubisoft said that a Jurassic Park type island with dinosaurs was one of the possible locations for Far Cry 5. This might yet turn into Foreshadowing.
- Historical references abound in Assassin's Creed, some of which can come off as cryptic background references. An interesting one, however, takes place in the Assassin's Creed III downloadable-content side-story "The Tyranny of King Washington." In the regular story, the PlayStation version of the game included extra missions in which Connor tries to stop Benedict Arnold from betraying West Point to the British, which were omitted from the others. In the DLC, which is set in an alternate timeline but with Connor aware of the events of the main story, he remarks that he finally got Arnold back for West Point when he kills him at the end of the first chapter. Arnold says that he has no idea what Connor is talking about, since in this timeline he never turned coat and thus never betrayed West Point. To Xbox and PC players who didn't get those missions, it comes off as a cryptic background reference, merely something that happened off-screen.
- In the main game and some others, conversations can be overheard in towns—particularly from heralds—referring to real historical events, such as a town crier in Assassin's Creed III informing citizens of events taking place in Egypt that have no bearing on the story at all. In Brotherhood—set in Renaissance Italy—a herald refers to the recent discovery of the New World and its native peoples.
- Anything to do with the First Civilization will have tons of this.
- Final Fantasy XIV like VIII above also does this alot. As it is an MMO, some of these references became fodder for patches and the Heavenward expansion, which focuses on the Dragonsong War, a war between Ishgard's theocratic society and Dravania's dragon and brings more of these with The Warrior of Darkness and bits and pieces found in the Dusk Vigil and Azys Lla's museum, the fallen Allagin Empire also stated out as such only to get some explanations with the Bonding Coil of Bahamut and Crystal Tower dungeons as well as the area of Azys Lla which explains how it became a Soiled City on a Hill and how its actions up to that point resulted in the Calamity much much later. In addition there are 7 Astral Eras and 7 Umbral Eras, the latter being caused by the end of a Golden Age. But only the events leading to the 4rd, 5th and 7th Umbral Eras (the latter being a transaction to and the time frame of the initial plot to A Realm Reborn) are known to the players, being the aforementioned fall of the Alagin Empire, the War of the Magi and the Calamity.
- Searching around Malet Island in the original Devil May Cry will reveal small details of the abandoned island's long dead inhabitants and their cultish worship of Big Bad Mundus. None of it ever amounts to anything, and some believe it to be a holdover from the game's time as a Resident Evil title. Dante himself will occasionally humorously lampshade that none of the island's history has any bearing on his quest.
- Foxhole's lore primarily exists of small bits of flavor text for maps, along with statue plaques, forgotten notes, and descriptions of view points that reveal tiny snippets of the setting.
- Girl Genius does this a lot, helping to give the sense that it's an alternate history defined by the presence of mad scientists.
- Among the more notable are references to what things were like before Baron Wulfenbach took over Europe, what the places ruled by less pleasant Sparks are like, and the fact that there are multiple popes.
- Occasionally they'll also drop and/or hide names we're familiar with in places we can spot them, showing how those individuals are different in this version of history (the most prominent one is actually reasonably well known, but he's addressed by his surname where we the reader are typically familiar with his given name alone). It's Rembrandt van Rijn.
- The most recent story arc in The Inexplicable Adventures of Bob! has involved a lot of clarification of throwaway details like this from earlier in the series. We've finally seen Butane the planet of dragons; we've gotten a minimally technobabblish explanation of what borfomite actually does; we've seen some court intrigue in the Nemesite Empire; Fructose Riboflavin is finally looking competent enough to explain how he got his terrifying reputation; etc.
- Dresden Codak engages in this from time to time. We never learn anything more about Reverse Moses, other than that he once parted the city to escape Aqua Pharoah.
- The Mansion of E often makes passing reference to things in distant parts of the Mansion's home country and continent.
- Several of these in The Sanity Circus, such as references to other, as-yet-unmet Scarecrows. Luther and Steven have also made reference to other Instrumen they know called March and Jupiter.
- All over the place in the Whateley Universe, because the authors have a huge bible they're working from. So there are references to superheroes and super-teams we haven't met yet, and supervillains who are 'A-level threats' according to an international scale we haven't had explained either, and also tons of references to real-world things to show how close that universe it to ours. Some of these are All There in the Manual. A B-List is world-threatening, but your average supergroup can still maybe win. Maybe. If they're lucky. An A-list, you have to call in EVERYONE. An A-list is the kinda guy you have for a Crisis Crossover.
- Also present in The Descendants, with characters mentioning minor villains they've defeated, superheroes in other cities, and seemingly pivotal moments in history that haven't even been explained in flashback. Whether or not they're just building up a Chekhov's Armoury, though, remains to be seen.
- Dr. Horrible's Sing-Along Blog makes mention to other superheroes/villains outside the main characters, such as Bait and Switch, Johnny Snow, and Hourglass, although some of them do get actual "screentime" in the supplemental comics.
- Limyaael's Fantasy Rants: Limyaael recommends that if you're going to use these for worldbuilding, use a lot of them, so the audience gets used to them as worldbuilding and doesn't expect them all to be plot points... and the ones that are plot points have the element of surprise.
- The earlier volumes of RWBY were full of references. Some of them deliberate hooks, others the result of difficulty dropping exposition about things the characters already knew. Most of the latter got filled in later on, but the series has so far kept up a supply of new hooks to replace things that are explained.
- Megatron in Beast Machines has a scar over one eye which he didn't have at the end of Beast Wars. Where did it come from? We don't know.
- Originally used, then later became a subversion during the pilot of Beast Wars. Optimus Primal references "the Great War." Since this series was originally not meant to be too closely connected to the first generation, this was more of a lore reference for longtime fans of the franchise, and this trope for everyone else. As the series went on and the creators decided to make the G1 connection more explicit, the original intent faded.
- The three-part pilot episode of Justice League shows the Big Seven superheroes working together as a team for the first time. This was Green Lantern John Stewart's and Hawkgirl's first appearance in the DC Animated Universe — and the established superheroes knew exactly who they were without any introductions, having apparently heard of their off-screen exploits or worked alongside them at some not-shown point in the past.
- Similarly, a lot of the superheroes and supervillains in Justice League just show up with their origins unexplained (and often never explained) as well; The Flash, Red Tornado, Vixen, Gypsy, Star Sapphire, Copperhead, Black Manta, and Doctor Polaris are just a few examples.
- Another big DC Animated Universe example - The Near Apocalypse of 2009, mentioned in Batman Beyond and Justice League Unlimited's Epilogue. Nothing is known about it except it was the last battle between the first Batman and Ra's al Ghul where Talia finally betrayed him for good. No other details are known about it, and so it has become a popular subject whenever fans demand more closure to the DCAU, although Word of God says they never really planned to cover the event in any of the animated shows, and at this point it does not seem like they ever will.
- Futurama often makes fleeting references to events that happened in the thousand years between 1999 and 2999, such as Conan O'Brien losing his legs in the War of 2012, most videotapes being destroyed in 2443 during the Second Coming, and the Sith War of 2865.
- Adventure Time has many references to a Great Mushroom War that happened about a millenia ago and that the world may have been like ours before this war.
- It goes further than that. It's gradually made clear that the world of Adventure Time is in fact our world plus a bit of Magical Realism, that eventually shifted into an outright Fantasy Kitchen Sink somehow. The Inferred Holocaust of such a dire change is obvious, as is the fact that our civilization didn't manage to survive it.
- For instance, one of the more daunting villains and terror incarnate, The Lich, has his home base in an abandoned derelict metropolitan subway station that survived the decay of millenia. Why the preference for a cityscape instead of the more typical and practical evil overlord lairs?
- Buildings and leftover architecture litter the landscape, but are quickly panned over as scenery all the time. A Freeze-Frame Bonus view of the Earth from space reveals that it's missing about 1/4 its mass, with a massive hole in the side.
- An ordinary movie with the standard disclaimer for home videos once appeared. Jake noted that it was from "before the Mushroom Wars". As in mushroom clouds?
- There are also more typical references, such as Billy the Hero's past exploits (He apparently managed to defeat the Lich, mentioned above, with Good Old Fisticuffs. Meaning, he somehow manage to punch him hard enough and for long enough against a tree that he became sealed in amber. That's the impression of events, anyway.) There was also a Rainicorn-Dog war and a group of Fish People who have colonized what may be, but is never confirmed as, a human fallout shelter. Etc, etc.
- In one of American Dad!'s Christmas specials, taking place on the post-Rapture Earth, inhabited by demons.
Stan: The open road is too dangerous.
Jesus: What if we go through Sector 16?
Stan: Sector 16? The perfect man just proposed the perfect way to die.
Jesus: Fine! Then what about Sector 35?
Stan: Sector 35? (scoffs) Sector 35 makes Sector 16 look like Sector 48!
- Star Wars: The Clone Wars had the Death Watch start working for the Confederacy in one episode and planning to kill their leader Count Dooku during their next appearance, where they were stranded on a snow world. Why this was happening was never explained.
- ThunderCats (2011) has the Cats searching for three stones of power, in addition to the Eye of Thundera. Where these come from no one knows. Also, the planet they live on is called Third Earth, and unlike in the original series, this one is heavily implied to not be our Earth, which means there must be a second earth. It's also implied that technology once existed in abundance even before Mumm-Ra's pyramid crashed there, which means it could be After the End.
- Young Justice manages to do this in a different way: back stories and origins often go unexplained, but will still be referenced. Your average DC fan won't be phased by characters mentioning the existence of Amazons or something called "the Guardians of the Universe," but it all adds up to a rather large, unexplored world.
- Steven Universe
- The show is always making reference to things that happened in the past that involved Gems, in particular the Gem war for Earth. The cause and purpose are eventually explained as the Crystal Gems splitting off from Homeworld to protect the native life, but the fine details are only vaguely alluded to, leaving thousands of years of history to explore. Additionally, many hints about the Alternate History shaped by Gems are brief images the camera's quick to pull away from. Among other things, there's a very large gap between the North and South American continent, Florida is an island some distance away, Madagascar is in the location of Brazil suggesting Africa and South America never split, etc.
- The Galaxy Warp is said to connect Gem-controlled planets to the Homeworld via Warp. Aside from Earth, there's an additional fifteen Warps that have been severely damaged, with nary a hint as to their names and possible native species. And there's likely newer Warp Pads constructed as Earth's Gem technology is severely out of date.
- The Venture Bros. features lots of The '70s style hero's and villains running around, we only see a handful of hero's but because of the big influence the Guild of Calamitous Intent have on the show we will constantly see cameo's from lots of weird looking Super Villain's. How and when the Guild started is also kind of vague but it's implied that it was formed by or because of Dr Ventures father or grandfather.
- South Park will occasionally mention weird origins for their various Monster of the Week.
- There's also the Coon Trilogy which gave vague origins for Kenny and Bradley, before he was born Kenny's parents where sought of members of the Cult of Cthulhu and they were somehow responsible for his Born-Again Immortality, as for Bradley he is a Human Alien living on Earth after some kind of war between two planets involving mint and berries.
- In "A History Channel Thanksgiving" it is revealed that Plymouth Rock was the site of a wormhole (More accurate it is the site that allows a wormhole to be opened from Natalie Portman's vagina) that connects to the planets Plymouth, Indi and a fourth one nobody cares abut (Green Lantern Homeworld).