Backstory

Backstory is what happened to a character before they arrived on the present scene. May exist for just one character, the entire cast, or the entire setting in which everything is taking place.

A good actor or writer has a strong sense of each character's Back Story, as it gives the character texture and shadings and keeps them from being two-dimensional. It makes an excellent source for The Reveal, and bits often are handed out: why The Rival resents The Hero so much; how the Fake Ultimate Hero got his reputation; why The Captain suffers from Bad Dreams. Hopefully, this is when the information is both plot relevant and likely to come up.

In fact, it can be so interesting and important that it's a wonder it's just a back story, and indeed, a particularly good Back Story can form the basis of a Prequel.

A good Retcon may go back and explore a character's Backstory. A Belated Backstory occurs when the Retcon radically and permanently changes a new character's personality. Some characters are given a Mysterious Past or Dark and Troubled Past as a backstory; these tend to be whatever the author wants, often retroactively growing, or changing.

Many Fanfics exist to explore Backstory (for example, how Spock's parents got together).

See also Prequel, Start of Darkness, Happy Flashback, Troubled Backstory Flashback, Backstory of the Day, When It All Began, and Standard Cop Backstory.

Anime and Manga
In Code Geass, this is provided by the sound and picture episodes.
 * Sket Dance, while a gag manga for the most part, features three separate backstory arcs for the main cast that are either sufficiently melodramatic (Bossun and Switch) or heartwarming (Himeko) that help flesh out their personalities and how they ended up becoming the people they are now.
 * Fullmetal Alchemist had quite a few chapters explaining Mustang and Hawkeye's backstories.
 * Don't you mean a
 * The Summer arc in AIR, which shows the beginning of the curse in the Jidai Geki.
 * Almost all of the characters of One Piece, especially the members of the Strawhat Crew.
 * In fact, a flashback featuring a character's (tragic) past is nearly always a dead giveaway that he/she will join the Strawhats by the end of the arc.
 * Oda used this to make us think two people might have join the crew; Vivi and Wiper. But, considering how lacking their pasts were compared to other Straw Hats, maybe it's not as much of a trick as you'd expect it to be.
 * Robin had joined the crew after the Alabasta arc, but her Dark and Troubled Past wasn't revealed until Enies Lobby, roughly three manga arcs later (five if you count the G8 filler arc in the anime and if you consider the Water 7 saga separate from Enies Lobby).
 * In the GetBackers manga, almost all the major characters, including villains, have complicated backstories peppered with angst and feuds. In every arc (except the minor filler types) there will be one or more flashbacks to explain new plot developments:
 * The Gundam Wing manga Episode Zero deals with the backstories of all the main characters that were originally meant to be in the anime. These stories explain many of the mysteries in the series - Duo's priest collar and Quatre's goggles being two examples - that are near essential to understanding the story as a whole.
 * Shonen anime such as Naruto or Bleach will often spend entire episodes - occasionally right in the middle of a major battle - delving into the backstory of a character as they gather their energy for a 'second wind' to get back into the fight. It most often takes place while they are (apparently) critically wounded... perhaps a nod to the old cliche of one's life passing before one's eyes.
 * Cowboy Bebop is interesting in that everyone has elaborate backstories, but only Faye's given any sort of complete explanation or chronology. You learn broad ideas, but never the whole picture: Spike was part of the Red Dragon Mafia, Jet was a police officer, Ein is a data dog (whatever that means) and Ed was in an orphanage after being abandoned by her father. The movie supposedly was intended to be a grand backstory for Spike, but the creators decided against it because it would probably never live up to the hype from the fans.
 * Berserk has such a long and complex backstory that it takes up twelve volumes of the manga and nearly the whole animated series. The backstory focuses mainly on Guts, but Griffith and Casca have their own pasts and motivations revealed as well. Serpico and Farnese also received their own backstory arc in the manga.
 * In Chrono Crusade, most of the important characters have backstories that connect them to the pasts of the other characters, especially in the manga. Chrono's is particularly important in driving the plot forward--so, of course, he avoids telling the other characters about it until late in the series.
 * Fakir's backstory in Princess Tutu is a key plot point, partly because he turns out to be and has.
 * Most characters in Yu-Gi-Oh!, even a lot of minor ones, get detailed backstories. This is especially true for the villains, and of course the main character, whose search for his unknown backstory forms the main plot.
 * Mahou Sensei Negima has a few chapters that go into Negi's backstory, explaining his motivations and where he got his goals.
 * Later on it goes into Asuna's backstory, which happens to be massively important to the current plot, even moreso than Negi's backstory.
 * An entire chapter of Death Note was devoted to Mikami's history, explaining why he embraced Kira so easily.
 * Yusuke, Kuwabara, Keiko, and Botan are about the only ones on Yu Yu Hakusho who don't get backstories...
 * The second Sound Stage of Magical Girl Lyrical Nanoha's first season revolved around Fate's life before the series began.
 * Detective Conan have most of its backstories concentrated to the Red Herring Shirt Akemi. Although she's been killed off very early in the series, she was first written as Dead Older Sister, and then our former mole CIA agent is revealed to be her boyfriend when he's still in The Syndicate.
 * Not strictly a manga (it's actually a manhwa) Rebirth has a colossal backstory that spans a full seven volumes. The author started and planned on it only being two volumes, maximum of three... then he got carried away and it grew to seven. Apparently the fans nearly revolted.
 * In the manga adaptation of Fruits Basket just about every character that appears has a backstory and many of them are connected. For example,
 * The plot of Game X Rush essentially revolves around the Backstory, most of which is held back entirely until the second volume.
 * Much of Pandora Hearts is trying to figure out the characters' backstories, in particular, how they all relate to the Tragedy of Sablier.
 * Ouran High School Host Club has a backstory for each of the hosts, often with a whole chapter devoted to one character's past. There's even a whole chapter dedicated to Haruhi's parents showing us how they met and fell in love. The anime has two entire episodes dedicated to flashbacks of how Kyouya and Tamaki met, and also how Hikaru and Kaoru met Tamaki and joined the Host Club.
 * Hajime no Ippo gives us episodes/chapters about how Kimura and Aoki as well as Takamura got into boxing. Sendo's backstory is also told by his grandma, but even more importantly, he gets his very own gaiden chapter which shows how the Naniwa Tomcat became the Naniwa Tiger. And yes, it is as badass as it sounds. There's also a flashback to Kamogawa's and Nekota's past, which involves Kamogawa beating a U.S. soldier in a boxing match.
 * Bleach. Almost every important character has been given some sort of flashback/backstory, and whenever one of the baddies is about to die, you can bet that there will be some form of a backstory.

Comic Books

 * Standard issue for heroes and villains, since everyone wants to know how X got her powers, why Y is called "the Red Rose," what happened between Group A and Group B to make them hate each other, and how it was that Everyone Went to School Together. One of the signs that a character is becoming popular or will get more screentime is when the writers give him a backstory.
 * Everyone who becomes a Ghost Rider has a detailed back story, and they're ALL subject to change.
 * For being such an obscure character until his movies, Blade had some history. Marvel did a pretty good job about taking from the movies without messing up his back story or character development in the comics he appeared in, until Marc Guggenheim Did Not Do the Research and then rewrote past events to cover his mistakes. To be fair, Blade's history was complex for an obscure character and Marc didn't want to write about him. Still could have done better for being paid.
 * In The Amazing Spider-Man, Mary Jane "MJ" Watson was the happy-go-lucky Veronica to Peter Parker's Archie...until she returned to the book in the early '80s after a few years' absence, and revealed at one point that she knew he was Spider-Man. In the following issue, MJ decided to confide in Peter, revealing her unknown back story. Turns out that she was laughing to hide the tears of her broken home.

Fan Fiction

 * Code Geass Mao of the Deliverance takes the titular Ensemble Darkhorse who only premiered for three episodes in the original Code Geass and introduces an in-depth, Perspective Flipped personal history which actually forms an engaging storyline that is both plausible and woven into established Canon very well, explaining How We Got Here.
 * during the Tamers Forever Series, Takeru tries to gain the trust of the Tamers, by revealing to them the true origins of not only the Digital World, but
 * A great deal of action hinges upon the back story of the world C'hou in With Strings Attached. The four are told the same story four or five different times, with new details emerging each time, until they finally know the original purpose of the Vasyn and what its return really means to the planet.
 * In The Tainted Grimoire, several were given.
 * explains during a lull in his battle with  what his motivations are and how he became the person he is at present.
 * We see bits and pieces of Sir Loin's life, including the development of his relationship with Adelle, during the chapter where.
 * Cheney explains to Tweigel his history with  before joining House Bowen and properly explains why he left House Bowen.

Film

 * The Star Wars prequel films had existed in brief notes just to get things together for the original movie. George Lucas wanted the original Star Wars to have the episode 4 title to resemble the Buck Rogers and Flash Gordon serials, but only used "Part IV" in the opening expository crawl. A New Hope has a lot of imagery that is intended to make you think you're seeing something familiar, such as the first appearance of Obi-Wan.
 * The eponymous Mystery Team once held the respect of the entire town; now they're nothing but a joke.
 * The Man Who Saves the World Info Dump prologue reveals a backstory bigger than many movies' plots that completely fails to make sense, as apparently mankind has homogenized in the Galaxy Age, and the Earth got blown up once or twice, but that's okay because they've built a force field made out of human brains to protect it now.

Literature

 * Since JRR Tolkien's Middle-earth stories (The Lord of the Rings, etc) span a world over thousands of years, and he wrote on it all his life, there is a lot of information on a variety of topics, history, and characters' lives. In fact, The Lord Of The Rings is more backstory with a novel than a novel with a backstory. Tolkien wrote the history of Middle-Earth as part of long running idea to create a British mythology that rivalled the far richer folklore such as Norse mythology. The novels themselves evolved out of this. His work went so far as to invent entire languages with their own character sets and long running genealogies detailing every major family, be they human, elf or otherwise.
 * The entire main plot of Harry Potter is rooted in the incredibly twisted tragic backstory of Harry's parents, their friends, and the events that led to their death. The other plot threads are a) an Ironic Echo of the backstory plot, and b) metaphors for overcoming your personal demons of the past (i.e., another echo of the plot).
 * Harry Potter establishes in detail a lot of the back story of Lord Voldemort, the principal villain, as well as the school life of Snape and Harry's parents.
 * Harry Potter does the same with Dumbledore, including
 * Don't forget about
 * One classmate of Harry's got a disproportionately large backstory: Dean Thomas. Rowling has written "I think Chris was slightly taken aback by the amount of information I had on this peripheral character."
 * Half the mystery in A Song of Ice and Fire is the backstory of the characters and Westeros itself.
 * CS Lewis's The Magician's Nephew is explicitly billed, in the text, as backstory to the rest of The Chronicles of Narnia books.
 * Both implicit and explicit in the Honor Harrington series, including the titular character. Generally, implicit in the "main" novels, explicit in the anthologies.
 * The "Horus Heresy" novels are the Backstory to the Warhammer 40000 universe.
 * Kavi has a particularly unpleasant one in Hilari Bell's Farsala Trilogy.
 * Explored a lot with different characters in the Warrior Cats series. There's The Rise of Scourge, Bluestar's Prophecy, Crookedstar's Promise, Yellowfang's Secret, and then a number of short stories in the field guides, such as the one about Barley's past. Even the main series has some of these moments.

Live Action TV

 * The second season episode of Buffy the Vampire Slayer, "Becoming, Part I," in which the audience sees how Buffy, Angel, Spike, and Drusilla "became" who they are today.
 * Buffy and Angel were both quite good at this- this (admittedly Buffy-lovin') troper can name the Buffy episodes "Amends" and "Lie to Me" and the Angel episodes "Darla," "Dear Boy," "Orpheus"... heck, a LOT of Angel is backstory contributing to various season arcs (Darla in Season 2, Holtz in season 3, etc.) as well as one or two "one-shot" backstory episodes such as "Why We Fight," the mentions of Angel's past in Vegas in "The House Always Wins," and "Are You Now or Have You Ever Been." Well, a guy does accumulate a lot of backstory in 240+ years of living...
 * The Firefly episode "Out of Gas" examined how the crew of Serenity came together. (It is supposed that Joss Whedon had planned much more detailed Backstories for certain enigmatic characters, but the series ended before they were revealed.)
 * Both Highlander the Series and Forever Knight were full of backstory; flashbacks where the events recalled served to illustrate present events. Being veeery long-lived characters, both Duncan MacLeod and Nick Knight had plenty of backstory to film.
 * Much of the plot structure of Lost (for the first three seasons at least) has centered on revealing the characters' backstories while showing how these pasts inform the characters' actions on the island.
 * The Supernatural pilot episode starts off with the backstory of how their mother got killed. Something Wicked introduced Dean's massive guilt/martyr complex, and A Very Supernatural Christmas revealed how he got his amulet.
 * The House episode "Three Stories" depicted how House ended up with his limp.
 * In two pieces of much happier backstory, "Birthmarks" told us that it, in a reversal of expectations, was actually House being a nice guy to Wilson (i.e bailing him out of jail because Wilson was having issues and getting divorced from his first wife) that started off their friendship and "Adverse Events" revealed that House was... a college cheerleader.
 * EVERYONE on House has some sort of backstory, and the story is ALWAYS a sad one. No one is allowed to be happy on House. You can only wonder how so many doctors with tragic pasts ended up in the same hospital.
 * Heroes had the first season episode "Six Months Ago" mostly showing the past of Peter and Nathan Petrelli, Claire Bennet, Matt Parkman and how Sylar first used his power. Then, seven episodes later, Company Man mixed a story in present with flashbacks of the past of Noah Bennet. The first half of the second season has a story with Hiro in the past, which also serves as a back story for a present villain Adam Monroe, concluding with the episode "Four Months Ago", which also served the back story of Maya and Alejandro Herrera. And finally the season three episode "Villains" explains how Sylar became a killer and his complicated relationship with Elle, how Arthur Petrelli ended up paralyzed, and why Flint Gordon got caught by Primatech and his sister Meredith did not.
 * Hell, the second to last episode gave a fairly large amount of backstory on Noah.
 * Higher Ground gradually reveals at some point or another (sometimes in the form of an Episode In The Spotlight) what got each of the Cliffhangers sent to Mt. Horizon.
 * Jericho - Almost everybody has an interesting history that gets at least a little attention, from what Jake was doing for two years to the relationship between Johnston and Gail (turns out she was 'the other woman').
 * Mad Men would be a much different show without the backstory of Dick Whitman
 * Star Trek is good for these.....
 * The Next Generation
 * Several episodes discuss Picard's time as captain of the Stargazer, his past with Dr. Crusher and her husband, and of course the fan favorite episode "Tapestry" discusses the young Picard back at the Academy.
 * One episode, describes and incident with Riker and his former CO, now an admiral. Another talks about his brave actions during a previous transporter accident that seems to have fast-tracked his career.
 * Several episodes dedicated to Worf's family, their disgrace, and Worf's childhood among humans.
 * Deep Space Nine
 * There are always passing references to former lives of the Dax character.
 * As the series went on, we learned how the Celestial prophets ensured the birth of Ben Sisko.
 * And of course, several references are made to the Cardassian occupation of Bajor, which has repercussions long into the show's run.
 * The Original Series
 * "The Conscience of the King" gives some insights into Kirk's childhood, describing a famine and related massacre that he witnessed at the age of thirteen. (It is unknown as yet whether this event has carried through to the new timeline.)
 * In "Obsession", the Enterprise returns to a planet that a young Lt. James T. Kirk conducted a survey on, sometime previous.
 * "The Menagerie", which was actually the first Trek pilot episode with heavy reediting, discussed Spock and the Enterprise under Captain Pike, the CO before Kirk took command.
 * "Space Seed" would serve as Backstory for The Wrath of Khan.
 * Babylon 5 had a vast back story. In the first season, events such as Earth's first contact with alien life, the Dilgar War that established Earth as a major power and the Earth-Minbari War that came within a hair's breadth of exterminating Humanity only to have the Minbari inexplicably surrender at the last moment. And that's just the Earth-related stuff: all the major alien races also had impressive back-stories, as did most of the characters.
 * Veronica Mars had a massive backstory that explained how Veronica, a formerly girly high school student, became a hard-boiled sardonic detective. Apparently all it takes is: 1) having the Sheriff be your father; 2) have your best friend murdered under mysterious circumstances; 3) have your father disgraced by the rich locals after he fails to close the case; 4) lose face with your peers because you stand by him; 5) go to a party with your peers only to get roofied and raped. The result? A jaded, cynical 17 year-old girl with an appetite for getting the truth--the perfect story telling recipe for awesome.

Tabletop Games

 * New World of Darkness has this as an option during character creation in the form of "Preludes." Which are essentially how the character you've made came to acquire/awaken/discover/what-have-you his or her powers. Vampires have Sires, Werewolves get their First Changes, Mages get their Awakenings, Changelings have Durances in Arcadia and so on.

Video Games

 * Halo has a surprisingly substantive backstory told through a multitude of novels, comics, Alternate Reality Games, guidebooks, online exclusives, live-action commercials, and even an anime series. Hell, one book trilogy is even set 100,000 years before the start of the games.
 * Portal has it's own ARG website with the Aperture Science backstory and how GLaDOS came to be.
 * The sequel also had several areas dating back to the 60s and 70s to explorer Aperture's rise and fall as company, as well as the origin of GLaDOS, revealing that she
 * Metal Gear Solid 3: Snake Eater and Metal Gear Solid Portable Ops establish the Start of Darkness of Big Boss, the Big Bad, showing his fall from a noble Badass Normal, through a quietly grieving Tragic Hero, into an Anti-Villain convinced that Utopia Justifies the Means. (His Utopia happens to be eternal World War.) However, pretty much every character has a backstory more in-depth and complicated than most real people's. Even if they're only on camera for fifteen minutes and are never mentioned again.
 * Darkstalkers started out simple but the sequel Night Warriors rewrote the character origins into surprisingly interesting back stories and Vampire Savior expanded it further, giving back stories to the different worlds the game takes place in.
 * Wing Commander has a fairly detailed backstory, told mostly in the manuals (including official game guides, and the Confederation Handbook for the movie) and novels, both novelizations of the games and new works within the setting.
 * BioWare uses player-party member dialogue to reveal backstory in Neverwinter Nights, Jade Empire, Knights of the Old Republic, Dragon Age, Mass Effect, and probably more.
 * All the playable characters, including minor ones, in any Fire Emblem between Genealogy and Radiant Dawn have at least some backstory and/or personality, which in some games can be explored through "support conversations". Path of Radiance and Radiant Dawn added base conversations that function similarly, but they're easier to get.
 * Each hero in Defense of the Ancients has some kind of backstory. Many of them are created by fans and put in the game.
 * Fallout has a rather extensive backstory as a result of taking place in an alternate history. The point of divergence seems to be somewhere during or immediately after World War II, and is used to explain the presence of rayguns, robots, and other Zeerust. It also explains why the US flag is different, and clarifies the origin and goals of the Enclave. All told, it's probably most relevant to Fallout 2 and 3.

Visual Novels

 * Fate/stay night has a backstory that is a major plot point for the story, the protagonist's entire motivation for existing (at least in the beginning), in fact. Most of the routes have his backstory as a point of major inner conflict for him over his ideals and his reality.
 * This particular backstory was fleshed out in its entirety in Fate/Zero.
 * Most of the other major character also have very important backstories, in particular Sakura and Rin. These are also covered, largely, in Fate/Zero. The backstory of Archer, however, is not well explained.
 * Tsukihime freaking exists because of this. The backstory is unbelievably complex and well-written, with each route giving off a small amount of information about the past. The entire backstory can be put together (like a puzzle) only after playing all of the routes.

Web Comics

 * A major part of Girl Genius is the slow unrolling of backstory. Much of the discussion in the various forums focuses on it, and the character moments are truly first-class. After the first volume, everything has been foreshadowed; there are no Ass Pulls. The central character, Agatha Heterodyne, has a backstory that is still not entirely revealed. The attack on Castle Heterodyne and the appearance of the mysterious The Other is, perhaps, on the verge of revelation as of this writing--nine and one-half volumes and about seven years into the series. A truly magnificent piece of through-plotting.
 * Pages and pages of Homestuck are completely dedicated to this. See the entirety of Act 5: Part One. All it does is discuss the Trolls and how they eventually
 * A minor example, but some pages are also dedicated to Cal's existence, Doc Scratch's existence, and how
 * Actually, the entire story can be considered a backstory to the Exiles, while also being a current series of events.
 * The Anachronic Order really blurs the line between story and backstory. Every so often the narrative shuffles the perspective point of 'the present' around, and settles only temporarily.
 * In Endstone -- lots. Starting with the way Kyri's estranged husband tried to destroy the world.
 * Details of the Valkyrie backstory in Cwynhild's Loom are slowly revealed in the comic, and a brief written history is available on the website.

Web Original

 * At its height, the Global Guardians PBEM Universe had literally megabytes of back story on its website, in a history involving thousands of characters and trailing all the way back to the Big Bang. When the game's website finally closed down, the administrator admitted that there was more back story that hadn't ever made it onto the website than information that had.
 * The Whateley Universe is powered by backstory. All but one of the major characters of Team Kimba (and some of the other main characters) had a full novel or novella covering how they got to the Super-Hero School Whateley Academy for their freshman year. Since then, we've seen backstory on everyone from the headmistress (who seems to have enough backstory for her own series) and the Chief of Whateley Security to side characters and even some of the villains. Word of God has revealed that the Canon authors are working from a 400-page 'bible' of backstories and characters and stuff that hasn't even been seen yet in the published material.
 * In The Gungan Council, all characters have some sort of backstory given in their first biography. However, in roleplays such as "It's Not That I Keep Hanging On, I'm Never Letting Go," the backstory for characters is described in detail to explain character relationships never written out before.

Western Animation

 * Even though the rest of the series has been relatively disowned by the fandom, a single Star Trek the Animated Series episode ("Yesteryear"), which explains Spock's backstory, is embraced. Curious.
 * No, what's embraced is how that story would've gone if adult Spock hadn't Time Travelled into it. It just happens that "Yesteryear" is the closest anyone has to that record.
 * In fact, because of that single episode, the entire series is officially canon. Fascinating.
 * In Phineas and Ferb, Dr. Doofenshmirtz has a backstory portion or something similar (That may have happened last week) for why he builds almost everyone of his -inators. Sometimes they're even animated.
 * In fact, Doofenshmirtz has come to look forward to his daily tales of woe, occasionally almost dancing as he exclaims, "Backstory time!"
 * K'nuckles has bouts of this in a couple of episodes in The Marvelous Misadventures of Flapjack. These are always brief, and rarely have anything to do with the plot.
 * Alvin and The Chipmunks had the first season episode "The Chipmunks Story", showing how Alvin, Simon, and Theodore were discovered by David Seville. The third season followed this up with, appropriately enough, "The Chipette Story", which explored the backstory of the Distaff Counterparts.
 * From Avatar: The Last Airbender, several characters' backstories are essential to understanding how they are in the present, particularly Zuko. Strangely, even though we see most of the main characters' backstories in the form of flashbacks, all we know about Iroh's backstory is vague statements by various characters who all know more than we do.
 * He Man and The Masters of The Universe: In the 80s cartoon, episodes give us back-stories to show us how Man-at-Arms became Teela's father, how Cringer first became Battle-Cat, how Orko first came to live at the Royal Palace, and how the Sorceress became the Sorceress.
 * In the 2002 series, we're given back-stories on the Sword of Power and King Greyskull, the same backstory for Orko as we saw in the 80s series (although he lost a wand this time instead of the original medallion), how Man-At-Arms became Teela's father (different to the 80s series) and how the Sorceress was able to become a mother in the first place.
 * "The Secret of the Swords" was the 80s set-up for the original She Ra Princess of Power series to give us the back-story on why Adam had a twin sister no-one had ever heard of.
 * My Little Pony Friendship Is Magic: "The Cutie Mark Chronicles" provides backstory to the "Mane Six", showing how each of them obtained their cutie marks.
 * And "Hearth's Warming Eve" tells the backstory of their kingdom, Equestria.
 * "Family Appreciation Day" has Granny Smith tell her backstory. It notably involves her
 * In the episode "The Call of The Squirrel Dog" of the 2010 version of Pound Puppies, the story of how helper squirrel Mr. Nut-Nut came to be part of the team was framed as a bedtime story for three puppies who, unfamiliar with his role, chased him around the lair.
 * In ThunderCats (2011), the episode "Old Friends" delves into the past friendship between Old Soldier Panthro and Evil Former Friend Grune, while "Into the Astral Plane" explores the childhoods of Cheetara and Tygra, including how the former became a Cleric.

Real Life

 * The Louisiana Maneuvers of 1941, largest exercise of the US Army to that date had an elaborate backstory drawn up whereby two fictional countries were "fighting" over the navigation of the Mississippi.
 * Everyone who you have ever met probably has a fairly interesting and complicated back-story to go with them.