History Fanfic / LegacySekiroKimetsuNoYaiba

It has been hundreds of years since Kuro, the Divine Heir, gave his life to prevent the Dragon's Heritage from falling into the wrong hands. Sustained by a drug to prolong his lifespan, the man once known as Sekiro has spent his days carving wood as the old Sculptor once did, desperate to stave off the allure of becoming Shura while guarding the Mortal Blade from those who would misuse it. Aside from infrequent visits from Tamayo, the daughter of his longtime friend Emma, and her assistant Yushiro, Sekiro expected to continue his vigil for as long as his mind would hold out.

* BladeOnAStick: Kiyoshi uses the Loaded Spear to disembowel Danzou with a lightning quick thrust.

** Kusabimaru, Wolf's most prized possession, is still in fine condition thanks to his dedicated care. Having been coated with lazulite and enchanted by all of the supernatural beings it has cut down, it is able to cleave through a demon's flesh almost as well as a Nichirin Sword.

* AdaptationalWimp: Wolf's skills have degraded after centuries without a worthy opponent to hone his skills against. While he's still a deadly warrior, he's not nearly as unstoppable as he once was and struggles against a single apparition. In addition, he has bequeathed the Shinobi Fang to Kiyoshi, leaving Wolf without an arm and the various Lazulite-enhanced tools he acquired throughout his journey. This is only relative to his original story though; in the setting of ''Demon Slayer'', he's still a force to be reckoned with.

* BagOfSpilling: Averted. The Shinobi Fang still contains all the Lazulite-enhanced weaponry Wolf acquired over the course of his journey. However, their effectiveness is blunted by Kiyoshi's inexperience and the powerful regenerative abilities of demons, necessitating the use of a Nichirin Blade to finish off a demon. However, the tools prove themselves to be just as effective against humans as they were before and are still useful for weakening demons even if they struggle to slay them.

* BroughtDownToBadass: With Kuro gone, Wolf no longer has his ResurrectiveImmortality. He also bequeathed the Shinobi Fang onto Kiyoshi, leaving Wolf without an arm and his many Lazulite tools. Despite this and time deteriorating his skills, he's still a fearsome opponent who is not to be taken lightly.

* SoLastSeason: While the Lazulite-enhanced tools in the Shinobi Fang are still deadly marvels of craftsmanship, they're incapable of bypassing a demon's regenerative abilities, necessitating a Nichirin Blade to deal lasting damage to the demons Kiyoshi faces.

* TheSleepless: Emma's and Dogen's drug has rendered sleep optional for Wolf. He takes advantage of this to continue running day and night to cover more ground while Kiyoshi sleeps on Wolf's back.

* ChildSoldiers: Kiyoshi is forced to fight the son and apprentice of a descendant of the Lone Shadows once slain by Wolf. He follows his father's orders to the letter, attempting to kill Kiyoshi without a hint of emotion and mocking him as week for throwing up after disemboweling his opponent.

** Kusabimaru, Wolf's most prized posession, is still in fine condition thanks to his dedicated care. Having been coated with lazulite and enchanted by all of the supernatural beings it has cut down, it is able to cleave through a demon's flesh almost as well as a Nichirin Sword.

* TheStoic: Wolf, as usual, rarely shows what he's feeling on his face. Even while downing the disgustingly bitter medicine keeping him alive and staving off the temptation of Shura, he doesn't even show a twinge on his face.

* DepletedPhlebotinumShells: Both wisteria flowers and Divine Confetti are poisonous to demons. Coating a weapon with one can allow it to damage or even kill a demon outright even if their head hasn't been cut off. Wolf uses the latter to purify a demon to kill it after he severs its head, while Kanae and Shinobu make use of the former as they aren't strong enough to sever the heads of demons with their petite physiques. However, stronger demons and spirits will require large amounts of Divine Confetti to kill them, and Wolf is forced to use six months worth of the stuff to slay a single apparition as dangerous as O'rin of the Water.

* SecretIdentity: Kyoichi keeps his identity as the One-Armed Fox a secret from everyone except those closest to him. When Makomo recognizes him with his mask on, he asks her to continue to refer to him as Sekiko until he takes it off to become Kyoichi again. AS if to emphasize this, Kiyoshi is referred to as "Fox" while acting as Sekiko.

* TheSleepless: Emma's and Dogen's drug has rendered sleep optional for Wolf.

* SurpassedTheTeacher: Discussed. Wolf plans to have Kiyoshi surpass him tenfold. But the author goes onto say that it's more important for Kiyoshi to inherit Wolf's will than become deadlier than Wolf.

* YouAreNotAlone: After observing Kiyoshi's SurvivorGuilt and thirst for revenge, Tamayo compares it to her own guilt at having killed and eaten her own family after being turned, and sits him down to tell him of that very sin before reminding him that he's not alone in his endeavors. She will always be there as a shoulder to lean on or someone to talk to. While it doesn't clear away all of his negative feelings, it does lighten his burden.

''Legacy'' is a ''Manga/DemonSlayerKimetsuNoYaiba'' and ''VideoGame/SekiroShadowsDieTwice'' {{Crossover}} Fic written by Xanothos. It follows Kiyoshi's journey toward becoming a legendary demon slayer and shinobi under the watchful tutelage of the former Sekiro.

It can be read [[https://forums.spacebattles.com/threads/legacy-sekiro-kimetsu-no-yaiba.792133/#post-61695682 here.]]

* AdaptationalWimp: Wolf's skills have degraded after centuries without a worthy opponent to hone his skills against. While he's still a deadly warrior, he's not nearly as unstoppable as he once was and struggles against a single apparition. In addition, he has bequeathed the Shinobi Fang to Kiyoshi, leaving Wolf without an arm and the various Lazulite-enhanced tools he acquired throughout his journey. This is only relative to his original story though; in the setting of Demon Slayer, he's still a force to be reckoned with.

* SymbioticPossession: When Zenitsu is struck by lightning, it doesn't merely turn his hair blonde in this story. He is also possessed by a Raiju, a hunting beast of the thunder god Raijin. Its soul has intertwined with his, cradling him like a mother would her cub. Once he lets go, the raiju helps him fight purely based on instinct, greatly speeding up his swings at the cost of technique in a state christened Wild Thunder. Even without technique, this allows Zenitsu to face the genius Kaigaku on even terms, and he would become a true force to be reckoned once he masters the Breath of Thunder's first form to perfection.
* TheSleepless: Emma's and Dogen's drug have rendered sleep optional for Wolf.

* ExpositoryHairstyleChange: As Kiyoshi devotes himself toward become Fox, he allows his hair to grow out and ties it up identically to Wolf's haircut, showing both his appreciation for his teacher as well as his desire to emulate the man who saved his life.

* PoisonedWeapons: Kanae and Shinobu dip their swords in poisons made from wisteria flowers and other materials toxic to demons to kill them even while lacking the strength to decapitate them. Wolf and Tamayo also teach Kiyoshi medicine and how to make similarly deadly toxins to coat his own weapons with.

** Kiyoshi is similarly loyal to Tamayo, having saved his life in the past. He instantly starts ranting when he feels that Tamayo has been disrespected and continually holds her in the highest esteem.

* YouAreNotAlone: After observing Kiyoshi's SurvivorGuilt and thirst for revenge, Tamayo compares it to a demon's ravenous hunger for human flesh and sits him down to tell him of her greatest sin before reminding him that he's not alone in his endeavors. She will always be there as a shoulder to lean on or someone to talk to. While it doesn't clear away all of his negative feelings, it does lighten his burden.

** Tamayo is introduced to the Pillars far earlier than in canon, not long after Kanae's death at Douma's hands,

* {{Ninja}}: Wolf is ''the'' ninja, the greatest to have ever lived. He teaches his skills to Kiyoshi as his successor.

* ExpositoryHaircutChange: As Kiyoshi devotes himself toward become Fox, he allows his hair to grow out and ties it up identically to Wolf's haircut, showing both his appreciation for his teacher as well as his desire to emulate the man who saved his life.

* ForWantOfANail: In this story, Kiyoshi calls out Kaigaku on his worst impulses and frequently challenges him, tempering Kaigaku's ego and making him [[AdaptationalHeroism far less antagonistic]]. At the Final Selection, he serves as TheRival to Kiyoshi and even works with him to dispatch the Hand Demon.

* JerkWithAHeartOfGold: Yushiro is standoffish to pretty much everyone save for Tamayo and Wolf. But he has served her faithfully for years becomes of how indebted he feels to her and selflessly plunges his hands into Divine Confetti to help Wolf kill an apparition with full knowledge of the burns he'd receive.
* KatanasAreJustBetter:

* WideEyedIdealist: Kanae Kocho firmly believes that humans and demons could potentially live together, seeing Wolf's and Tamayo living under the same roof as proof that her ideal can be realized.

* ChildSoldier: Kiyoshi is forced to fight the son and apprentice of a descendant of the Lone Shadows once slain by Wolf. He follows his father's orders to the letter, attempting to kill Kiyoshi without a hint of emotion and mocking him as week for throwing up after disemboweling his opponent.

* SecretIdentity: Kyoichi keeps his identity as the One-Armed Fox a secret from everyone except those closest to him. When Makomo recognizes him with his mask on, he asks her to continue to refer to him as Sekiko until he takes it off to become Kyoichi again. AS if to emphasize this, Kiyoshi is referred to as "Fox" while acting as Sekiko/

* YouAreBetterThanYouThinkYouAre: Yushiro thrashes at a metal training dummy in frustration, lamenting his weakness and fearing that when Muzan came for Tamayo, he'd be useless to do anything about it. Wolf consoles him, reminding Yushiro that it was his decisive action that prevented him from having to draw the Mortal Blade. Kiyoshi also pipes in, nothing that Tamayo's chi is brighter and happier when she's around him, assuring Yushiro that his presence alone is a comfort to her.

* MasterSwordsman: Even after centuries of atrophy, Wolf is a deadly swordsman on par with any of the Pillars. He and Tamayo are evenly matched despite her demonic strength and constant practice.

* SymbioticPosession: When Zenitsu is struck by lightning, it doesn't merely turn his hair blonde in this story. He is also possessed by a Raiju, a hunting beast of the thunder god Raijin. Its soul has intertwined with his, cradling him like a mother would her cub. Once he lets go, the raiju helps him fight purely based on instinct, greatly speeding up his swings at the cost of technique in a state christened Wild Thunder. Even without technique, this allows Zenitsu to face the genius Kaigaku on even terms, and he would become a true force to be reckoned once he masters the Breath of Thunder's first form to perfection.

* {{Foil}}: Kiyoshi and Uzui walk similar yet diametrically opposed paths. Kiyoshi is an ordinary boy who becomes a shinobi and a demon slayer to enact vengeance for his mother. Meanwhile, Uzui becomes a demon slayer to leave the shinobi life and find happiness. Their Breath Styles are also both derived from the Breath of Thunder, but are complete opposites. Uzui's Breath of Sound utilizes chi to create shockwaves for massive destructive power, while Kiyoshi's Breath of Silence utilizes chi to mask his presence for silent, nearly imperceptible attacks.

* PsychoSerum: The ability to become Shura is explained as a tincture developed in the past to improve one's combat abilities many time over. Wolf had consumed it during his tutelage under Owl, and has been struggling against the urge to become Shura ever since. Knowing full well what it did to him, Wolf refuses to let Kiyoshi even learn of its existence, lest he be tempted to imbibe it.

* SymbioticPosession: When Zenitsu is struck by lightning, it doesn't merely turn his hair blonde in this story. He is also possessed by a Raiju, a hunting beast of the thunder god Raijin. Its soul has intertwined with his, cradling him like a mother would her cub. Once he lets go, the raiju helps him fight purely based on instinct, greatly speeding up his swings at the cost of technique.

* AuraVision: Kiyoshi's clan, the Ametsuchi, had the innate ability to perceive the chi of others. Kiyoshi believed that he was the only one left who could until he meets Wolf. As a result, the elemental effects of the different Breath styles are explained as an expression of the chi of a particular demon slayer.

* ForWantOfANail: In this story, Kiyoshi calls out Kaigaku on his worst impulses and frequently challenges him, tempering Kaigaku's ego and making him far less antagonistic. At the Final Selection, he serves as TheRival to Kiyoshi and even works with him to dispatch the Hand Demon.

* SecretIdentity: Kyoichi keeps his identity as the One-Armed Fox a secret from everyone except those closest to him. When Makomo recognizes him with his mask on, he asks her to continue to refer to him as Sekiko until he takes it off to become Kyoichi again.

* AdaptationalWimp: Wolf's skills have degraded after centuries without a worthy opponent to hone his skills against. While he's still a deadly warrior, he's not nearly as unstoppable as he once was and struggles against a single apparition. In addition, he has bequeathed the Shinobi Fang to Kiyoshi, leaving Wolf without an arm and the various Lazulite-enhanced tools he acquired throughout his journey. This is only relative to his original however; in the fic he's still one of the strongest beings in the story.

* AdaptationalWimp: Wolf's skills have degraded after centuries without a worthy opponent to hone his skills against. While he's still a deadly warrior, he's not nearly as unstoppable as he once was and struggles against a single apparition. In addition, he has bequeathed the Shinobi Fang to Kiyoshi, leaving Wolf without an arm and the various Lazulite-enhanced tools he acquired throughout his journey. This is only relative to his original however; in the fic he's still one of the strongest beings seen on-screen thus far.

** Kiyoshi is similarly loyal to Tamayo, having saved his life in the past. He instantly starts ranting when he feels that Tamayo has been disrespected and continually holds her in the highest esteem.

* OriginalGeneration: Kiyoshi is an original character designed to take up the role of Sekiro.

* AdaptationalWimp: Wolf's skills have degraded after centuries without a worthy opponent to hone his skills against. While he's still a deadly warrior, he's not nearly as unstoppable as he once was and struggles against a single apparition. In addition, he has bequeathed the Shinobi Fang to Kiyoshi, leaving Wolf without an arm and the various Lazulite-enhanced tools he acquired throughout his journey.

** Yushiro is also this, as his Blindfold technique conceals him from all of the mundane senses. He even made sure that he was tasteless. To his chagrin, those used to sensing chi or killing intent can still feel him coming.

* DepletedPhlebotinumShells: Both wisteria flowers and divine confetti are poisonous to demons. Coating a weapon with one can allow it to damage or even kill a demon outright even if their head hasn't been cut off. Wolf uses the latter to purify a demon to kill it after he severs its head, while Kanae and Shinobu make use of the former as they aren't strong enough to sever the heads of demons with their petite physiques. However, stronger demons and spirits will require large amounts of divine confetti to kill them, and Wolf is forced to use six months worth of the stuff to slay a single apparition as dangerous as O'rin of the Wa

* HeartbrokenBadass: Wolf continues to mourn his lord's death, mentoring Kiyoshi in Kuro's name.

* NoStatAtrophy: Averted. Sekiro's skills have atrophied from hundreds of years of inactivity. He's still a formidable swordsman and warrior, but he's no longer the unstoppable OneManArmy who has slain gods and dragons. Wolf acknowledges this, as his swings are rough and jagged compared to the CleanCut he once doled out regularly.

* StealthExpert: Wolf trains Kiyoshi to be this as an essential part of being a shinobi. This goes so far as to become the basis of Kiyoshi's unique Breath style, the Breath of Silence, which [[PerceptionFilter erases his presence from other's perception.]] Even from the keen senses of the average demon struggle to locate him, giving him an opening to land a decisive strike.

* DepletedPhlebotinumShells: Both wisteria flowers and divine confetti are poisonous to demons. Coating a weapon with one can allow it to damage or even kill a demon outright even if their head hasn't been cut off. Wolf uses the latter to purify a demon to kill it after he severs its head, while Kanae and Shinobu make use of the former as they aren't strong enough to sever the heads of demons with their petite physiques. However, stronger demons and spirits will require large amounts of divine confetti to kill them, and Wolf is forced to use several months worth of effort to slay a single

* DepletedPhlebotniumShells: Both wisteria flowers and divine confetti are poisonous to demons. Coating a weapon with one can allow it to damage or even kill a demon outright even if their head hasn't been cut off. Wolf uses the latter to purify a demon to kill it after he severs its head, while Kanae and Shinobu make use of the former as they aren't strong enough to sever the heads of demons with their petite physiques. However, stronger demons and spirits will require large amounts of divine confetti to kill them, and Wolf is forced to use several months worth of effort to slay a single

* NoStatAtrophy: Averted. Sekiro's skills have atrophied from hundreds of years of inactivity. He's still a formidable swordsman and warrior, but he's no longer the unstoppable OneManArmy who has slain gods and dragons.

* {{Revenge}}: Both Kiyoshi and Tamayo are motivated by revenge. Kiyoshi wants revenge on Douma for killing his mother and cutting off his arm, while Tamayo wants vengeance on Muzan for turning her into a demon and making her devour her own family.

* ElixirOfLife: Tamayo gives Wolf regular doses of a medicine developed by her grandfather Dogen to keep Wolf alive in his vigil over the Mortal Blade. As a result, Wolf no longer needs to eat, drink, [[TheSleepless or sleep]] to survive, nor will he age or sicken. However, he falls short of CompleteImmortality in that he can still be slain, which is a comfort to him, as he shudders to think about the possibility of an unkillable Shura should he ever give into his innate urges.
* FusionFic: The story merges the settings of ''Sekiro'' and ''Demon Slayer'', with the events of the latter taking place hundreds of years after the events of the former. Wolf has lived this long thanks to a drug developed by Emma that is still being administered to him by her daughter, Tamayo.

* OriginalGeneration: Kiyoshi is an original character designed to take up the role of Sekiro.

* AdaptationalBadass: Due to being the daughter of Emma in this story, Tamayo has been trained in the Ashina-style of swordsmanship, making her a frighteningly dangerous opponent to cross on par with Wolf himself.

''Legacy'' is a ''Manga/DemonSlayerKimetsuNoYaiba'' and ''VideoGame/SekiroShadowsDieTwice'' FusionFic written by Xanothos. It follows Kiyoshi's journey toward becoming a legendary demon slayer and shinobi under the watchful tutelage of the former Sekiro.

Spoilers for ''Sekiro'' will be unmarked. '''You Have Been Warned'''