Death by Flashback

Basically, if a character experiences an extended flashback sequence, often explaining his origins and, especially, getting rid of all the loose ends in his Backstory, there is a good chance that he is going to be Killed Off for Real. If this is combined with gloomy omens, such as cracking pottery or falling flower petals, he is almost certainly done for.

A subtrope of A Death in The Limelight. Somewhat related to My Life Flashed Before My Eyes, Really Dead Montage, except it happens before the character's death. Can be part of a Sympathetic Murder Backstory. See also Retirony and Fatal Family Photo.

Anime And Manga

 * Naruto loves this trope though subversions also appear. Fans often joke about a character going down with "a terminal case of flashbacks".
 * Lampshaded in a recent Filler episode, when a character begins flashbacking in mid-battle and is immediately convinced that his own death is imminent. He even defines flashbacks as visions of the past that a person sees just before their death.
 * Bleach is quite similar. Well, except that it will never be terminal, unless the character in question is a hollow or a Filler Villain.
 * In the Cowboy Bebop's Grand Finale, we finally get to see what went down between Spike and Vicious, something that had just been hinted at earlier. Guess which two that are going to end up killing each other...
 * The Trigun episode, Paradise, focuses a lot on Wolfwood and he dies at the end.
 * This is what literally happens to Carossea Doon in Madlax: his memory returns in a flashback and reveals that he has actually been Dead All Along for twelve years.
 * Regius Gaiz and Zest Grangaitz of Magical Girl Lyrical Nanoha StrikerS, who both get killed soon after we receive a flashback that reveal their Backstory.
 * Surprisingly, this was used in Pokémon. Ash's Bulbasaur was at Oak's lab helping bring a stop to some territorial disputes, when a bolder falls. It looks like it was crushed, with a series of flashbacks playing highlights of of Bulbasaur from the series. Bulbasaur used Dig and popped up a few seconds later.
 * L has an oddly expository dream about his childhood before he dies in Death Note.
 * Episode 25 of Fullmetal Alchemist places heavy focus on the relationship between Maes Hughes and Roy Mustang during flashbacks, and gives Maes in general a lot of attention. He was doomed

Literature

 * This happens to Durza at the end of Eragon. The "flashbacks" happen immediately after Eragon deals the guy a fatal blow. Durza, is a Shade, and is thus a highly magical creature. The flashbacks are the result of his soul attacking Eragon's and trying to corrupt and kill him. So he's trying to cause Eragon to have a case of death by someone else's flashback.
 * Severus Snape in Harry Potter, though technically he dies before the flashback scene, not after, and the need for the flashback is caused by his dying.
 * Almost the entirety of Frankenstein is a flashback narrated by Victor Frankenstein to the explorer Walton. He dies not long after finishing his tale. There's also a possible aversion here, as the Monster narrates a flashback within a flashback, and his fate is left ambiguous at the end. He says he's going to kill himself, but we don't see it happen.
 * Averted and Played With in the Dresden Files. Harry dies, he recounts his origin story as a ghost, walks into the light ... and wakes up in Mab's arms.

Film

 * The entire movie American Beauty is a flashback from the main character, Lester Burnham, as he recounts the year before his death. In fact, he is telling it from the afterlife.
 * Similarly, Ladder 49 is about a firefighter who is trapped in a very large burning building after saving someone's life and is unsuccessful in escaping, with flashbacks involving his career, marriage, and family making up the bulk of the movie.

Live Action TV

 * Shannon, Ana, Eko, Nikki, Paolo, and Faraday in Lost. Subverted by Charlie whose final flashback episode is about him coming to grips with his impending death, and preparing himself for it. Due to a Prophecy Twist the end of the episode, he is still alive. He dies in the next episode, after the spotlight has moved on. Juliet might also qualify, as said character did have a flashback in her (possibly) final episode, even though the episode was centered on another character. And the character said episode was centered around, Jacob, also seemed to meet his doom by the end.
 * On Angel Fred got both extended flashbacks before she was taken over by Illyria and a Really Dead Montage after she died and Illyria took over.
 * Kamen Rider Dragon Knight. Normally, we get a Rider's backstory soon after meeting him, but Torque's past remained a mystery for most of his arc. Guess what happened to him soon after we find out his history?
 * In Supernatural Season 3 we finally find out why Bela was being targeted by the ghost ship almost literally a minute before her death. She had made a contract with a minion of the Big Bad ten years earlier to kill her abusive father and neglectful mother. For some it was an Alas Poor Scrappy moment, but mileage varies.
 * The Sheriff in Once Upon a Time dies in the episode where we learn his fairy-tale identity.

Opera

 * In Götterdämmerung, Siegfried tells the hunting party the story of his youth (i.e., most of what happened in Siegfried), and the orchestra supplies the appropriate Leitmotifs. Hagen gives him a potion that makes him remember something he had previously forgotten about: the story of how he first met Brünnhilde. Gunther is shocked, because she's now his wife. A few moments later, Hagen plunges his spear into Siegfried's back.

Video Games

 * After failing to cast suspicion on Falsetto, Claves of Eternal Sonata is killed by one of the people she was working with. She does not, however, die immediately; we have to watch several snippets of conversation from earlier cutscenes, some extremely recent. This is mingled with musing on why she failed, both in her mission, and in her love life.
 * There was also the part where, while in Baroque, Polka and Beat recall what they went through to get to the castle. The scene shifts to a really long flashback in which the player takes control, and if the party is killed by the pirates that attack, you get a game over.
 * In Infinity String, the protagonist starts an interactive flashback sequence. In two of the endings (an early bad ending and the good ending), the protagonist is killed by a Grandfather Paradox.

Web Comics

 * Mosp from Sluggy Freelance got her own flashback mini-arc immediately before being getting killed off quick.

Western Animation

 * Bleeding Gums Murphy in The Simpsons reveals a whole bunch of previously unmentioned backstory about him before he dies in the episode "'Round Springfield". There's also a hint that he may be Dr. Hibbert's long-lost brother, but it never goes beyond a brief throwaway joke.
 * Ted Kord in Batman the Brave And The Bold. He is, of course, not quite the Blue Beetle focused on for this show, but his extended flashback shows how he was as a character and the legacy Jaime must live up to.
 * In Avatar: The Last Airbender we know in the first episode that the Fire Nation killed Jet's parents,but then we see it all in flashbacks in the episode "Lake Laogai", which is his last episode. In fact we see the flashbacks in fast mode just minutes before a failed attempt at Throwing Your Sword Always Works.