This man/woman/creature is a One-Man Army, they have killed countless people, their power and skill are known throughout the world... Only that happened a while in the past, and by now they're dead.
This trope is about badass characters who are discussed by the cast sometimes, sometimes stories are told about him, frequently flashbacks are included in visual media. However, this character has been dead since before the series began. This character is frequently a family member of one of the main protagonists or villains, a mentor who taught the good guys and/or bad guys everything they know, a legendary figure from ages past, or sometimes all 3, but whether it be from old age, battle, or other cause, this character is dead prior to the story. By definition this character can usually only be referred to by someone else or appear in flashbacks, but never actually appear, however if the story has time travel in its repertoire this character can sometimes appear physically in the story, but that is pretty rare.
If the character is dead and brought back to life at some point, that's Back from the Dead, which invalidates this trope if said person remains alive for some time, but it's only fairly briefly it still applies. If this character is believed by most everyone to be dead but turns out to not be, that's Not Quite Dead. If this character dies, goes to the afterlife and fights their way out, that's Escaped from Hell. If this character is defeated, but not killed and instead sealed away, that's Sealed Badass in a Can. If they are prophecised to return someday, that's King in the Mountain. If this character dies during the actual story, no matter how early, then it is Square Peg, Round Trope. If the character is brought back as an undead to assist the heroes, that's Cavalry of the Dead. This character is sometimes the motivation for a Roaring Rampage of Revenge, sometimes the character is someone the main characters aspire to be, maybe being that MC's Can't Catch Up. Unlike Famed in Story, this character doesn't actually HAVE to be famous, just important enough to the to one or more of the main characters to be mentioned sometimes. Frequently the inverse of Living Legend. A type of Posthumous Character.
This is a death trope, unmarked spoilers ahead.
- In the Anime version of AKIRA, the people searching for the eponymous character eventually discover he has been Dead All Along, leading to a Downer Ending.
- Baki the Grappler: By the start of the series, he's been long dead (implied to be of old age), but Yuuichiro Hanma, father of Yujiro and grandfather of Baki, was just as, if not more of a monster of immeasurable strength than even his son, the world-(in)famous "Strongest Creature on Earth". He fought in and survived the Pacific Campaign, skirmishing with the USS Iowa battleship by using a technique to hurl enemy soldiers like missiles. The Okinawan island he was on was regularly fire-bombed and shelled, and it wasn't enough to kill him. The commanding officer even explicitly intended to try dropping a nuke on him, and was only stopped because the larger war had ended already, though that didn't stop him from continuing with the rest, only to end up a mangled corpse embedded in the hull of his ship. Cementing his status within this trope, Yuichiro even manages to return to the 21st century as a specter to oversee the climactic battle between son and grandson, where his presence alone manages to cause the inhumanly strong caveman Pickle to violently shake with fear, even though the series up until that point contained very few supernatural or even semi-supernatural elements.
- In Demon Slayer: Kimetsu no Yaiba, Yoriichi Tsugikuni, the legendary demon slayer who singlehandedly propelled the Demon Slayer Corps to become a force that actually posed a threat to demonkind, before Yoriichi the corps was just a band of Samurai with completely human abilities fighting for their dear life against the lowest of the low weak demon, but Yoriichi was a gifted man, thought to be divine by some, with an unique body condition that made him the inventor of "Breathing", a form of superhuman control over one's respiration that unlocks the control over all muscles and blood circulation, turning mere humans into super athletic individuals that could then make short work of any weak demon. Yoriichi himself was the strongest demon slayer that ever lived, so strong that even the strongest demon in the series, and progenitor of them all, Muzan Kibutsuji looked like a mere weakling demon when facing Yoriichi, Muzan only escaped death by his hands due a string of distractions and Muzan's complicated escape maneuver. Despite Yoriichi losing his prestige by being expelled from the Demon Slayer Corps that he helped so much after being blamed for the disaster that was Muzan escaping, a demon that assisted Muzan, Tamayo, being spared by Yoriichi since he could feel something good inside her after she was freed from Muzan's control, and on top of all Yoriichi's own older twin Michikatsu betraying the corps to become Muzan's number one demon, Yoriichi's contribution by inventing Breathing techniques has turned into the main practice of the demon slayer corps for centuries to come, a tool of body improvement that simply is their only hope of ever fighting against demons in a fair playing field.
- In Inuyasha, the title character's father is a demon lord said to have been one of the most powerful demons of his time, both of his sons aspire to be as strong or stronger than he is, and many plot points throughout the series occur because of machinations he set in motion prior to his death. However, he ends up dying from his injuries fighting Ryūkotsusei, a dragonlike demon.
- Lyrical Nanoha has the last Sankt Kaiser, the Queen deemed second to none in combat who sacrificed herself to stop the Ancient Belka War, an act that led to her being worshiped as a Christ-like figure in The Multiverse. Nanoha in her Super Mode could barely keep up with an untrained clone of hers during the climax of Magical Girl Lyrical Nanoha StrikerS, and flashbacks in Magical Girl Lyrical Nanoha ViVid shows her curb-stomping other powerful legendary figures from her time.
- Moribito: Guardian of the Spirit has Jiguro, a spear-wielding badass who trained Balsa. He dies of an illness a few years prior to the story.
- Hashirama Senju, the First Hokage is the man that shaped the current existing shinobi system and ended years of conflict, something that was thought to be impossible during his time. Not to mention he can squash Bijū/Tailed Beasts flat if he feels like it.
- Tobirama Senju (Hashirama's brother and the Second Hokage) and Minato Namikaze (Naruto's father and the Fourth Hokage) both fit for this trope, to about equal amounts.
- Madara Uchiha was a contemporary and rival of Hashirama, revered as the most powerful Uchiha ever. Hashirama killed him in a duel that carved a canyon into the surface of the planet. However, Madara resurrected himself with Izanagi and managed to live until 12 years before the start of the series, when old age finally caught up to him. Before dying, he passed his name and legacy on to Obito Uchiha, and was later brought back as a zombie by Kabuto and briefly managed to fully resurrect himself, but died a third and final time after having the Ten Tailed Beast extracted from him.
- One Piece has the King of the Pirates Gold Roger, over twenty years dead. Only the World's Strongest Man, Whitebeard, was said to ever fight on equal terms with him. One of the big secrets surrounding Roger's capture and execution is the fact that he was never actually captured, Roger surrendered and used his death to spark the Great Pirate Era.
- In the first few issues of Savage Dragon, the hero known as Mighty Man had been dead for a few weeks. He shows up later in the series. Or at least, one of him does.
- Wonder Woman (1987): Diana's aunt Antiope has been dead for centuries, but once led the contingent of Amazons who were furious at the gods for punishing them for fighting against Hercules and his men for drugging and raping them and founded the Bana tribe of Amazons from which Artemis hails.
- Assassin's Creed (2016): Aguilar died 490 years before Callum Lynch was put in the Animus. Due to the ability of the Animus, Callum and the audience get to see how badass he was when alive.
- Snowpiercer: An unnamed Inuit maid led The Revolt of the Seven, an intricate plot against Wilford, many years ago (Minsoo had some involvement with it), but the plan failed and ended in her death.
- The Star Wars Expanded Universe has enough examples to take up its own page, many of which later appear alive in EU material, either as main characters or adversaries.
- In Turning Red, Mei's ancestor, Sun Yee, was a One-Woman Army when she was alive during the Ming Dynasty.
- In The Lost King the last English king to die in battle, Richard III, is portrayed as this. Additionally, when they find his skeleton, they realize that he was also a Handicapped Badass.
- The series (most notably Jingo) makes frequent mentions of Tacticus, an ancient Morporkian general who was renowned for his military expertise to the point that the word "tactic" was coined in his honor. He was unique among Morporkian generals in that he actually cared more about winning battles and keeping his men alive than "glory" measured by how many people died on either side.
- Sam Vimes' ancestor "Stoneface" is another example
- Averted, inverted and played with in the form of Cohen the Barbarian, the veteran hero who (especially in earlier appearances) is a hero who has outlived his time... but is still alive.
- J. R. R. Tolkien has dwarfs routinely cite their ancestors. In particular, Thorin Oakenshield mentions Thráin, King Under The Mountain during the pilgrimage to Lonely Mountain in The Hobbit. Thráin is said to have routed the dragons in the area, and amassed a huge treasure horde in his mountain's caverns.
- In James Clavell's Noble House, tales of Tess "Hag" Struan's long, cunning, and ruthless rule-behind-the-throne through successive tai-pans (chief executives) of Struan's Trading Company, and her dealings with hers and the company's enemies, were commonly discussed by the main characters, some perhaps embellished a bit. They were definitely in awed respect for her legacy though. Clavell's previous novel Tai Pan, set over a century before when the company was founded after the British purchase of Hong Kong Island, did depict her rise to power and influence as a younger lady and showed that there was probably a lot of truth to those later tales, though.
- Literature/Scholomance: Sir Alfred Cooper-Browning founded and built the schoolmance in 1886 and personally led an expedition attempting to repair the scouring device to make it safe for graduating classes four years later. They completed enough repairs to save the next three years worth of graduating classes before Sir Alfred was eaten by a maw-mouth. He isn't technically dead, but he might as well be, and would be a lot happier if he was.
- A whole heap in A Song of Ice and Fire. Notably, Rhaegar Targaryen, Arthur Dayne, Gerold Hightower. Brandon Stark probably qualifies, too. Aemon Targaryen The Dragon Knight is widely viewed as the greatest Kingsguard and finest knight to ever live.
- Historical figures mentioned in this category include Serwyn of the Mirror Shield, Symeon Star-Eyes (both of whom lived before knighthood was even a thing but are so legendary that they are honorarily considered the first knights) and Galladon of Morne The Perfect Knight.
- Cold Case: Viv's father in "WASP", although it's unclear how long he's been dead. He taught her to be a crop duster, and insisted on flying bombers during the war even though the government offered to make him a training instructor due to his age. He was killed in action as a result.
- For the Klingons of Star Trek, Kahless is the ultimate example.
- Warhammer is full of undead, but Lord Kroak, Slaan Mage-Priest of the Lizardmen, is a straight example: one of the oldest beings on the planet, he died several thousands of years ago defending his doomed city, using his last seconds to cast a spell so powerful it leveled the city and killed every demon miles around, and has remained dead since then, even though the Warhammer setting has a tendency to have people come back to life in various states. His corpse remains extremely magic and is taken into battle by the Lizardmen because the sheer magic power emanating from his remains is a huge death-sphere centered on him, which spares only Lizardmen.
- Warhammer 40,000 has its own examples (Generally in the form of Space Marine Dreadnoughts, near-dead Marines in a life-support coffin in a giant robot). A notable example is Bjorn the Fell-Handed, who fought alongside the original Space Wolves, 10,000 years before the events of 'present Warhammer 40K', and died in battle. He infrequently gets called back from lifelessness to fight for the Wolves.
- Generally subverted, as having 10,000 years of lore explored over decades means that often the 'long dead' badasses will get flashback works, but for ones that fit it straight? Macharius, essentially Alexander the Great and Sun Tzu's child (who died several hundred years before the present day of the setting), Horus on the villain side, the God-Emperor himself probably qualifies though he is under And I Must Scream rather than dead. The entire cast of Horus Heresy is basically exploring these guys. Among the Primarchs, Ferrus Manus for the loyalists, along with the aforementioned Horus Lupercal and Konrad Curze for the traitors, all three of whom are actually dead rather than missing in action.
- This comes up throughout Assassin's Creed, both in individual games and just by the fact that the games are usually set centuries apart from each other (or just several decades for the more recent games). Assassin's Creed II, set in Renaissance Italy, directly addresses the previous player character, who lived in Syria during the Third Crusade, and Altaïr himself is a Long-Dead Badass to pretty much any installment set after the Crusades. Ezio becomes one to the next protagonist, Connor Kenway, who along with Shay, Haytham, Arno becomes one to the Jacob and Evie Frye in Syndicate, with Connor's grandfather Edward and his quartermaster Adéwalé being between Connor and Ezio. Internally, Captain Kidd is a Long-Dead Badass to Connor, and unlike these other characters never physically appears. To top it all off, just about every single character in the entire franchise is a Long-Dead Badass to the characters in the present-day Framing Device, especially Desmond Miles, who is descended from most if not all of the player characters.
- Chrono Trigger. Cyrus was Glenn's AKA Frog's best friend and Knight Captain of Guardia, who's sword skills are second only to Frog's own. He dies fighting Magus, sacrificing himself so that Glenn could escape some years before the middle age time period begins. He also appears briefly as an apparition during one of the game's sidequests.
- Dante's father, the demon Sparda, is dead by the time the Devil May Cry games take place. He's renowned for rebelling against his demon kin and saving humanity from them, which is no small feat, and he even got known as the "Legendary Dark Knight" because of it. Dante has taken up his legacy, but we never got to see Sparda himself in action. Interestingly, the series never states exactly how he died, and the only game-related source where he's directly confirmed as dead is in the prologue of the first game.
- The Elder Scrolls:
- There are countless in the series' backstory. Pelinal Whitestrake, Wulfharth Ash-King, Ysgramor, Reman Cyrodiil, Tiber Septim, Uriel Septim V...and that's just naming the Imperial and Nord examples. More details about them (and more) can be found on the franchise's Historical Figures character page.
- To the Dunmer people, most prominently shown in Morrowind, Indorial Nerevar is this. He is the Founder of the Kingdom and the Tribunal rule in his name (though they may very well be responsible for his death). He's been sainted by their church and is held up as the standard all Dunmer should aspire to be.
- The Khajiiti people have one in Rajhin, the legendary Impossible Thief who is credited with, among other things, stealing the Ring of Khajiiti off the arm of the Daedric Prince Mephala, stealing a tattoo off the neck of the sleeping Empress, and stealing the entire city of Falinesti. A beloved thief, however badass, may seem strange to an outsider, but to the Khajiit (who are a very pragmatic race with no word for "rules" in their language), it is quite justified. In modern times, Rajhin is considered the God of Thievery to the Khajiit.
- In Skyrim, the three First Tongues trained on how to use the Thu'um by the repentant dragon Paarthurnax, by the time the game rolls around. Gormlaith, Felldir, and Hakon are referred to by Paarthurnax as "wuth fadonne", or "old friends"; for an ageless dragon like Paarthurnax to refer to them like that shows how much they meant to him.
- The Vault Dweller from Fallout. At the very least, he was 16 by the time Fallout started in 2161. He defeated several gangs, and even a Super Mutant army. 120 years later, by the time of Fallout: New Vegas (2281), he's probably dead (unless he had been ghoulified at some point), as he would be 136 years old at the very least, but his status as a legend still holds. He appears in the non-canonical Fallout: Brotherhood of Steel where the player can kill him in an optional sidequest in the game's second act, despite them being on the same side earlier.
- The Champions in The Legend of Zelda: Breath of the Wild were four warriors chosen from their various races to pilot the Divine Beasts based on their preexisting skills in combat. They were killed in the Great Calamity when Ganon took over the Divine Beasts with his evil essence, and a century later people both praise their deeds and lament their deaths (especially the Zora princess Mipha, due to her people being Long-Lived and personally remembering her from back then). Link and Zelda are assumed to be this, but both are actually still alive through supernatural means.
- Suikoden III has the Flame Champion.
- Played for Laughs in Tales of Monkey Island. Guybrush finds himself trapped in a whale along with an inept crew of pirates. The exception is Santino, a real man among men, a guy whose innumerable talents would be invaluable in getting out of the situation. Of course, he's been dead long before Guybrush got there.