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->''"The Masamune... That sword is cursed with hate and sorrow... Anyone who lays his hands on it will be overcome with negative sentiments and will be driven mad..."''
-->-- '''Radius''', ''VideoGame/ChronoCross''

In many stories with fantastical or sci-fi elements, there's one particular object or weapon that the heroes rely on -- perhaps a CoolSword or OrphansPlotTrinket that just so happens to be the source of their powers. It will always be stated as innocent or innocuous at the least, and outright holy at the most extreme. In both cases, this is the hero's trademark weapon and the crutch by which they battle and carry out their adventures; if it's of the sacred variety, the heroes may use it as [[OmniscientMoralityLicense a crutch for the morality of their actions, too]]: Sure, it might leave a bad taste in their mouths to have killed the sympathetic AntiVillain or the TragicMonster, but they have their holy sword! They must have the forces of Good behind them, so it's all right!

Unfortunately, in cases like this it's not that pretty -- this weapon or object works through [[EvilWeapon evil means]]. Perhaps it's PoweredByAForsakenChild, or perhaps it's a keystone in the villain's EvilPlan, and he's [[UnwittingPawn manipulating the heroes]] into [[MacGuffinDeliveryService handing it over to him]] or powering it up for him. And of course, it could have ''originally'' been truly a holy weapon, only to have been [[TheCorruption corrupted]] into an {{evil|Weapon}} one at some point in the past.

TheReveal of this information is expected to be proportionately dramatic to the item in question's plot importance. Depending on what point in the plot the truth comes out, a variety of outcomes can occur:

* If the truth comes out early in the plot, viewers can expect a brief HeroicBSOD or TenMinuteRetirement in which the heroes attempt to cast aside the item in disgust. Sometimes they can find another power source, although usually they are persuaded to keep using it until the world is saved, when they can stop using it safely.
* The hero may attempt to purify the Unholy Holy Sword so that it [[BecomingTheMask really can be used safely and in the name of good]]. (This doesn't work with PoweredByAForsakenChild examples unless you can find a different power source -- maybe one that works even better!).
* If the Unholy Holy Sword is plot-important or TheReveal occurs during the climax or penultimate stage of the story, the plot may very well shift in the direction of sealing or destroying it so that no one can use it again, if not a full-on dramatic confrontation with the villain over its true purpose.

Not to be confused with SealedEvilInACan, where the object ''contains'' something evil; this ''is'' innately bad. Related to the AmuletOfDependency, the EvilWeapon, and the ArtifactOfDoom, where an item like this is ObviouslyEvil. Contrast with HolyIsNotSafe, where even without being "unholy" it is still a dangerous item.

Sometimes may be an ArtifactOfAttraction -- the very reason you wanted that sword so desperately in the first place was because it was messing with your head.

The MacGuffin and AppliedPhlebotinum's reply to TheMole.

Needless to say, '''this is a SPOILER trope''', so if you happen to be spoiler-sensitive, avert thine eyes.
----
!!Examples:

[[foldercontrol]]

[[folder:Anime & Manga]]
* The [[HumongousMecha Evangelions]] from ''Anime/NeonGenesisEvangelion'' are touted as the only weapon capable of protecting the world from the [[EldritchAbomination Angels]] and [[TheEndOfTheWorldAsWeKnowIt The Third Impact]]. Turns out that A) They're cloned from angels themselves and powered by [[spoiler:human souls -- in this case, the souls of the pilots' mothers]] -- and B) They were created to [[spoiler:''initiate'' Third Impact... on SEELE's terms. And not even SEELE could truly control the power they were messing with. The Third Impact that actually happens is nothing like what they wanted.]]
* In ''Anime/NightWizard'', the seven Jewels of Virtue the heroes are collecting turn out to be fragments of (God of Destruction) Shaimal's power. Once the Jewels are brought together, Shaimal begins to awaken within Eris, who's horrified upon learning that she's just a vessel for Shaimal's reincarnation.
[[/folder]]

[[folder:Comic Books]]
* The eponymous Amulets from ''ComicBook/{{Amulet}}''. Sure, they enable to you to do neat things like lift objects, shield people, and attack, but they also [[spoiler:expose you to an evil spirit that was responsible for a deadly civil war between the elves, and is responsible for the Elf King and Max spreading misery throughout the land due using the King's corpse as a puppet, and manipulating Max's anger over his friend's death]]. Also if you're not careful and rely on it too much, the Amulet will devour you.
* Creator/DCComics:
** ''ComicBook/GreenLantern'':
*** The Red and Orange Power Rings. Not only are they powered by rage and greed, respectively, but their wearers become consumed with those emotions as well. Yellow Power Rings are fear-based, but their wearers generally retain their personalities.
*** The Violet Power Rings are powered by love and cause their wielders to become [[InLoveWithLove obsessed with it]], though not to the extremes of the original Star Sapphires. This is partially due to the brainwashing most recruits go through before they are taken into the Corps.
** The DC Universe has the Anti-Life Equation, which isn't this because it's the ultimate proof of the pointlessness of free will that itself seems driven to erase all life. It's existence was hinted by the knowledge of the Life Equation, something that allows the wielder god-like power that should [[RealityWarpingIsNotAToy never be wielded by mortal minds]]. In the hands of the unscrupulous, or [[WellIntentionedExtremist well intentioned but flawed]], it can be used much like Anti-Life as a tool of dominance by rewriting victims into loyal followers. Using an incomplete Life Equation instead mutates targets into feral monsters.
[[/folder]]

[[folder:Films -- Animation]]
* The Creator/{{Disney}}[=/=]Creator/{{Pixar}} movie ''WesternAnimation/MonstersInc'' ventures a inversion. The monsters use the screams of small children to power... well, everything. Nobody thinks this is bad, as they're convinced children are toxic. After inadvertently scaring Boo, Sully finds a new source of energy: children's laughter, which is 10 times more powerful. Also, children aren't really toxic, just very energetic.
[[/folder]]

[[folder:Films -- Live-Action]]
* In the movie ''Feng Shui'', the lead character receives a "lucky" ba gua mirror. It is in fact lucky, in the superficial sense, but it also turns out everyone who looks in the mirror dies according to their Chinese zodiac sign.
[[/folder]]

[[folder:Literature]]
* ''Literature/TheElricSaga'': The Black Sword(s) (of which Stormbringer and its twin Mournblade are incarnations of) were actually made to fight against Chaos and any other threat to the multiverse. It's just that the Melnibonean Emperors used them to fight anything else as well. The big revelations were in finding out how important Stormbringer is to the cosmos (instead of being just a really hard-hitting magic sword) and just how evil it truly is (Elric underestimates this to great cost).
* ''Literature/HarryPotter'':
** Voldemort's Horcruxes were intended to be something like this. He bound several pieces of his soul to legendary relics of the Hogwarts founders (holy, perhaps in a "civil-sacred" sense), thus seeking to blend his evil ambition with their glory. Use of these "sacred" relics causes addiction and would eventually destroy the pawn using the object.
** Harry's InvisibilityCloak is revealed in the [[Literature/HarryPotterAndTheDeathlyHallows final book]] to be [[spoiler:[[TheGrimReaper Death's]] own cloak! [[UnreliableExpositor Maybe]]. What is for certain is that it is one of the 3 eponymous Deathly Hallows, 3 powerful magical artifacts that Death himself may or may not have made. Subverted however, in that the the series' [[AnAesop Aesop]] is that [[DontFearTheReaper Death is not necessarily harmful]]. On top of that, the Cloak is at the very least the most benign of 3 Hallows; while the other two have a tendency to bring their owners to early graves, the Cloak is said to allow its user to hide from Death as long as possible, living a long life until they're finally ready to [[FaceDeathWithDignity "greet Death again like an old friend."]]]]
* The Subtle Knife from Phillip Pullman's trilogy, ''Literature/HisDarkMaterials'' is initially presented as a useful tool. It can cut through dimensional barriers and enables the majority of the plot to happen. However, not only are the holes it creates [[spoiler:drawing out the Dust that powers all sentient life in the universe, but using it creates horrific monsters that eat the soul of any adults (i.e. Dust magnets) they find. Iorek is reluctant to reforge it when it breaks and Will breaks it deliberately when it is no longer needed]].
* In the ''Literature/InheritanceCycle'', the sword Eragon gets from Brom, Zar'roc, is later found out to have belonged to the last of the Forsworn, Morzan, who was killed by Brom. This is emphasized when Eragon finds out what "Zar'roc" actually means (''Misery'').
* Over the course of ''Literature/TheHobbit'' and ''Literature/TheLordOfTheRings'', the One Ring is treated something like this -- it's Bilbo's most prized artifact and gets him out of a lot of trouble, but once its true nature is exposed, it takes a narrative six times longer than the first book to destroy it safely.
* In ''Literature/MemorySorrowAndThorn'', the eponymous swords the protagonists believe they need to gather to stop the [[BigBad Storm King]] are actually the key to his return. This becomes the third version, as, after the reveal, the focus of the story abruptly shifts to how to ''stop'' the bad guys from using them. Of course, [[YouAreTooLate they are too late]], forcing the heroes to TakeAThirdOption.
* In the ''Literature/SecretHistories'' novel ''The Man with the Golden Torc'' by Simon R. Green, it's revealed that the golden armor that the Drood family wears, that makes them super powered and indestructable, are powered by the souls of their dead twins which are consumed by The Heart (a giant, living crystal with godlike powers) shortly after birth.
* In ''Literature/TheSecretsOfTheImmortalNicholasFlamel'', the elemental swords are well known -- one is Excalibur. They also all actively consume the memories of those wounded by them, and eventually the minds of an unprotected wielder, and can potentially destroy the world if united. The heroes use one. Oops.
* Gurthang, the sword of [[IronWoobie Túrin Turambar]] in J.R.R.Tolkien's ''Literature/TheSilmarillion''. It enables him to slay the dragon Glaurung, but it also claims the lives of many of his friends and loved ones, and [[DrivenToSuicide in the end his own]]. (It's a very hungry sword and it will drink the blood of anyone, including its wielder.)
* ''Literature/{{Slayers}}'': Gourry's weapon, the Sword of Light, is a legendary artifact which generates [[LaserBlade a blade of pure light]] in response to the user's willpower. It's initially described only as a family heirloom, a holy weapon passed down from a hero who defeated the Demon Beast Zanaffar... but during the Gaav arc {{Demon Lords|AndArchdevils}} and their direct subordinates are also shown to recognise it on sight, referring to it as "Gorun Nova". This culminates in Gourry using the Sword of Light to attack Hellmaster Phibrizo, only for Hellmaster to laugh at the "shallow-minded name" humans gave the weapon, and cause it to sprout tentacles of darkness which attack Gourry. He reveals that Gorun Nova is actually a living demon from another universe, created as one of the personal weapons of [[GodOfEvil Darkstar]], and promptly sends it back where it came from.[[note]]At least in the novels. Every adaptation has Gourry keep using the sword for a while after this, with the AnimatedAdaptation even having [[AdaptationExpansion a season-long plotline about bringing all five Darkstar weapons together]].[[/note]]
* In ''Literature/ASongOfIceAndFire'', the legendary hero Azor Ahai reportedly forged his magic FlamingSword Lightbringer by [[LoveSacrificedForPower quenching it with the life's blood of his beloved wife Nissa Nissa]]. The way the story is told in-universe, the moral is supposed to be that great good can only be accomplished through great sacrifice. As characters such as Stannis attempt to re-create the legendary hero's accomplishments, the real lesson seems to be that overwhelming (and near-uncontrollable, self-destructive) power can only be attained through repeated acts of violence and ruthlessness. No end of grief has been caused by would-be {{Chosen One}}s trying to fill Azor Ahai's shoes.
* ''Literature/TheStormlightArchive'': This is disturbingly implied in ''Literature/TheWayOfKings2010''. Shardblades are the only weapons humanity possesses that can harm the demonic Voidbringers, but then you discover that Sylphrena, a being literally MadeOfGood, gets antsy around them and thinks Dalinar is a better man for getting rid of his. The truth is revealed in ''Literature/WordsOfRadiance''. As it turns out, Shardblades are [[spoiler:spren like Syl, who learned how to take weapon form through their bonds to the Radiants. When the Radiants broke their oaths, the bonds also broke, killing (in a manner of speaking) the spren they'd bonded to. Syl's revulsion to the shardblades is because they are the bodies of dead spren, ''constantly screaming in agony''.]]
* ''Literature/TheSwordOfGood'': The titular Sword of Good really ''is'' a weapon designed to smite evil and promote goodness - but it is ''completely dishonorable''. It {{Mind Rape}}s the protagonist with traumatic visions of victims throughout history, until they are convinced to betray and murder their party for being not-so-good, and accepts the hand of a [[{{Hypocrite}} corrupt wizard]] because he's [[TheLastDJ also one of the few people fighting for the actual side of good]] and not for TheEmpire.
* ''Literature/{{Warbreaker}}'' features the sword Nightblood. It was created as a permanently Awakened object, infused with the command to "Destroy evil". The intent was to create a weapon with the command to do only good and the will to carry it out. In practice, this backfired dramatically. What seems like a simple command to a human mind proved terribly vague to an object like a sword. Nightblood, as a sword without human experiences, doesn’t have a concept of what evil ''is'', and doesn’t have the capacity to learn, though it claims it’s trying. Nightblood’s need to consume Breath (an energy bestowed with one’s soul) to function also causes it to drain the life of its wielder. What was intended to be a force for good became a weapon that controls any with ill intent who wield it, destroying everything in its path (on the off chance that there will be ''some'' evil to destroy along the way), until the user is compelled to kill himself as well. Only someone truly devoid of evil intent can even look at the sword without being controlled, and it takes a divine store of Breath to wield it safely regardless. In that way, Nightblood at least acts as a decent way to ''detect'' evil
* ''Literature/TheWheelOfTime'' has Callandor, the Sword That Is Not A Sword. As a ''sa'angreal'' crystal sword that [[AmplifierArtifact shines with light whenever the wielder channels the One Power]], it has all of the trappings of a true holy sword. Except... it's flawed, lacking a buffer to prevent the wielder from using too much of the One Power, and can ensnare the wielder in a trap. Worse, though, is that it's revealed that [[spoiler:it is also a ''sa'angreal'' for the [[BlackMagic True]] [[DangerousForbiddenTechnique Power]], the essence of [[BigBad the Dark One]]. In the end it's subverted - the trap is sprung on one of [[QuirkyMinibossSquad the Forsaken]], and the Dark One's prison is rewoven out of [[YinYangBomb his own essence and the One Power combined]].]]
[[/folder]]

[[folder:Live-Action TV]]
* In ''Series/BuffyTheVampireSlayer'', The Slayer is humanity's guardian against evil, which includes but is not limited to vampires. Then it turns out the power of the Slayer line began when the First Slayer was imbued with the power of a demon.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/BraveFencerMusashi'' features Lumina, the [[DepartmentOfRedundancyDepartment sword of luminescence]], which was used to defeat the Wizard of Darkness in the distant past. Musashi claims it early in the game, and spends most of the rest of it finding and claiming the [[PlotCoupon Five Scrolls]] that increase its power. Naturally, upon acquiring the final one, it turns out that Lumina wasn't just used to defeat the Wizard of Darkness, the Wizard of Darkness was [[SealedEvilInACan sealed inside of it]] and the scrolls have been [[NiceJobBreakingItHero breaking the seal]].
* ''VideoGame/ChronoTrigger'':
** The Grandlion/Masamune is a complicated example. It's first mentioned as a heroic knight's blade, but turns out to have been filled with the power of [[EldritchAbomination Lavos]], but is also powered by a pair of playful spirits that react to people's dreams. So it goes from good, to bad, to neutral, to good again. By ''VideoGame/ChronoCross'', it's been tainted again (by a powerful person wielding it for evil). It is purified again after the spirits' older sister Doreen shows up to chew them out for misbehaving and joins them. It then becomes the Mastermune, Serge's strongest weapon.
** ''VideoGame/ChronoCross'' has the Records of Fate, which are revered in Arni as if they speak some divine and benevolent will, but it turns out they're used to control the islanders by [[spoiler:the aptly-named supercomputer FATE]].
* ''Videogame/DarkSouls'' features Artorias the Abysswalker, who turned his signature greatsword, which had divine properties, into a cursed blade capable of harming the ghosts residing in New Londo. [[spoiler:His sword is tainted again in the Downloadable Content, this time by Manus, turning it into the Abyss Greatsword.]]
* Characters in ''VideoGame/DemonsSouls'' [[UnequalRites make a point of distinguishing]] magic/soul arts, which is demonic power, from miracles, which are empowered by faith in God. However, despite clerics disdaining soul arts, they never think too hard as to why ''both'' abilities only work in the same [[FogOfDoom Colorless Fog]] that demons dwell in... [[spoiler:Sage Freke outright believes the God clerics worship is the Old One, and that seems to be why he abandoned religion for soul arts. Allant, however, knows the Old One is the ''source'' of both miracles and soul arts, but sees it as a creation of God.]]
* In ''Videogame/DawnOfWarIII'', countless people have fought and died trying to claim the legendary Spear of Khaine on the world of Acheron. The Spear is prophecised to unite the Eldar people and lead them to victory. The Eldar Autarch Kyre is especially obsessed with claiming it due to being a narcissistic GlorySeeker. [[spoiler:The Spear turned out to be nothing but an elaborate trap. It was no weapon of an Eldar god. A powerful daemon was sealed in Acheron, and it used the Spear to lure people to it who would fight and die for it. When Kyre tried to finish off Gorgutz with the Spear, its tip shattered and unleashed dark energies that claimed Kyre himself as the final sacrifice needed to free the daemon.]]
* ''VideoGame/TheElderScrollsIVOblivion'''s "Knights of the Nine" expansion has a variation, where there is a sword that is holy (wielded by a powerful time traveling berserker-saint who was a robotic xenophobic personification of a missing god, no less) that was cursed afterwards by someone who used it in a war for material conquest.
* ''Franchise/FireEmblem'':
** Implied at the end of ''VideoGame/FireEmblemFates: Conquest''. [[spoiler:After spending the entire game coming further and further under the sway of Anankos, Takumi wields a dark bow called Skadi as the FinalBoss. Its physical similarity to his normal divine weapon, the Fujin Yumi, strongly suggests that Skadi is its corrupted form.]]
** The Hero's Relics of ''VideoGame/FireEmblemThreeHouses'' are said to be gifts from the Goddess Sothis. In reality? [[spoiler:They're made from the bones of her murdered children, and the most powerful of them, the Sword Of The Creator, is made from her spine.]] Also, while they do grant quite a few bonuses to people who can wield them properly (such as unique combat arts), they [[spoiler:drain HP from people without Crests at best, and [[PainfulTransformation painfully transform them]] into horrible monsters at worst]].
* Kite's Bracelet from the ''[[VideoGame/DotHackR1Games .hack R1]]'' games [[spoiler:was the heart of Cubia, the most dangerous enemy the party had ever encountered, and needed to be destroyed before said enemy could die.]]
* ''VideoGame/HeroesOfMightAndMagic 4'':
** The game has the Angel's Blade. It's not necessarily evil, and its primary function is killing undead and demons, but a quest during the campaign reveals it was created by a demon. It doesn't really matter since 1) the main character is a necromancer fighting other demons, and 2) he only needs the sword because the energy released when destroying it will open a portal to where he needs to go.
** The last campaign of ''Heroes Chronicles'' revolves around the Sword of Frost, an extremely powerful sword which is being sought by the Barbarian King [[AxCrazy Kilgor]] as a counter to Gelu's Armageddon's Blade, by Gelu to destroy Armageddon's Blade and keep the Sword of Frost out of Kilgor's hands, and by Tarnum to both keep it out of Kilgor's hands and keep Gelu from destroying Armageddon's Blade in the wrong way. Sadly, the wrong way that the Sword of Frost ends the terror of Armageddon's Blade is what happens... and it is by ''[[EarthShatteringKaboom blowing up the world]]'', leading to the events of [[VideoGame/HeroesOfMightAndMagic HOMM 4]].
* In ''VideoGame/HyperdimensionNeptuniaMk2'', the main characters can come across the Gehaburn around half way through the game, leading to the infamous [[EarnYourBadEnding Conquest Ending]]. [[spoiler:In order to gather power for it, Nepgear is forced to kill the [=CPUs=] and their sisters, ''including her own sister''. Even worse, turns out this is what the BigBad wanted all along, as with only Nepgear rulling Gameindustri, [[NiceJobBreakingItHero its demise is inevitable]]. Thankfully, in the ''[=Re;Birth2=]'' remake, you have the option to gain a true holy sword without any sacrifices.]]
* ''VideoGame/MortalKombatDeception'' introduces us to Ashrah, a Netherrealm demon who fights [[MySpeciesDothProtestTooMuch for redemption]], aided by the Kriss (a sword with a wavy blade) she wields, that guides her into slaying evil beings. However, ''[[VideoGame/MortalKombatArmageddon Armageddon]]'' reveals, in [[ExcusePlot what little backstory it has]] other than being essentially a DreamMatchGame, that the Kriss is actually a KnightTemplar weapon called Datusha, who just wishes to kill stuff while giving its wielder the illusion that they're slaying evil creatures for a greater good. And it's especially harmful to [[OurVampiresAreDifferent Vampires]], thus giving Nitara (who is more on the ChaoticNeutral side of things) a motivation to join in on the fight, as Ashrah is unknowingly driving her people to extinction.
* The ''Neverland'' games by Creator/IdeaFactory invert this with a whole slew of weapons with more or less ominous names that turn out to be potent forces of good. Among others, Demon Princess Hiro's Gate of Hell scythe can sunder someone's soul from their body and send it straight to Hell, but only works on those with an extremely evil spirit, and the Evil Spear Aleph-Beth was the weapon of choice of Arth, a holy angel who ascended to godhood and, in spite of his sudden fit of rage against humans at one point in history, was actually one of the few ascended gods who WEREN'T homicidal maniacs.
* In ''Videogame/PhantomBrave'', Sprout was once the greatest of the Four Swords of Ivoire and wielded the Sacred Sword. After his family was slain by the demon Sulphur, Sprout became obsessed with vengeance and decided to fight fire with fire by absorbing dark energy from the demons he hunts. Sprout's once Sacred Sword became an unholy blade of darkness.
* A fundamental game mechanic of the [=PS2=] reboot of ''VideoGame/{{Shinobi}}''. Your character is chosen to wield the cursed Akujiki (after having to duel his older brother to the death for ownership of the sword), a soul eating sword that regularly drains your health unless you are constantly slaying enemies. Boss fights, which are often one-on-one, can get frustrating because of this.
* Soul Calibur of the ''VideoGame/SoulSeries''; a crystalline weapon of justice that is supposed to turn back the evil that is Soul Edge. However the inhabiting spirit turns out to be [[KnightTemplar as bad as the sword it's designed to counter]], believing that the world is unfit to continue as it is with warfare and disconcert running rampant and the only solution is eternal serenity through nothingness.
** The backstory of several Korean characters involves their trying to find the "Sword of Salvation" in order to drive out the Japanese. At first they thought it might be Soul Edge, the MacGuffin pretty much everyone else is after. After seeing its evil true nature in ''Soul Calibur II'', they spend the rest of the series warning people of its manipulative nature, and trying to destroy it with Soul Calibur. Then Talim makes them realize Soul Calibur is just as bad.
* ''VideoGame/{{Sudeki}}''; the first half of the plot revolves around collecting crystals to power a "Peace Shield" around the kingdom of Haskillia, protecting it for all time. As it turns out, the crystals actually gain their power by sucking the "light" (akin to LifeEnergy) from the mirror dimension of Akloria, leaving it to essentially rot as Haskillia blooms. To say nothing of the machine's real purpose, summoning [[ManBehindTheMan Heigou]].
%%* Blastia in ''VideoGame/TalesOfVesperia''.
* Arcadion the Shade Sword, or The Black Sword, from ''VideoGame/UltimaVII: The Black Gate'' (the Forge of Virtue expansion). Forged from a supernatural metal and empowered by its captive demon, it is a superb weapon that can kill almost anything that is capable of dying, possesses many other potent powers, and the demon can offer plenty of advice on matters. On the other hand, it is a ''demon-powered sword'' and you're supposed to be the Avatar, a champion of Virtue. It's fairly far-fetched for you to want to wield the thing, or forge the cursed thing in the first place. You can avoid it by not completing the expansion, but since you start with it in ''Serpent Isle'', Arcadion is canon.
* ''VideoGame/WarcraftIII'':
** Frostmourne was originally the sword of [[MagnificentBastard Ner'zhul]] [[BigBad (the Lich King)]]. He tricked Prince Arthas into using (which he did, believing it was the only way he could defeat the plague of the undead), while its true purpose was to corrupt Arthas into joining him.
** The Ashbringer zig-zags around this trope. The crystal that it was made of started as evil, but was purified. The sword itself was created as good, later corrupted, and then purified again. And then there are theories that the crystal is somehow related to [[CrystalDragonJesus Naaru]], or ''is'' one, going through their dark/light reincarnations. And then in ''Legion'', players who unlock its [[BraggingRightsReward hidden appearance]] corrupt it ''again''. It can't seem to catch a break.
** Quel'Delar, the InfinityMinusOneSword of ''VideoGame/WorldOfWarcraft: Wrath of the Lich King'', goes through this stage briefly during the quest to reforge it. When it's been reforged with saronite, an ore that is actually the blood of a major EldritchAbomination (MadeOfEvil, of course), it draws its owner to the vicinity of Frostmourne and attacks on its own accord. After that, it too needs to be purified.
* The Guardian Blade from ''VideoGame/WildArms'' and its re-use in Million Memories. The sword is not in of itself evil and can channel the powers of the [[BigGood Guardians]] themselves. However, when the sword was first used the wielder lacked the inner strength to properly control its immense power, resulting in it going berserk, destroying humans and demons alike, and creating the Ocean of Sand (the desert that cuts across the planet). In the end, only [[TheHero Rudy]] proves able to control a ''small fragment'' of the sword fused into his left arm because his metal body and ARM abilties.
* The Monado in ''VideoGame/XenobladeChronicles1'' is valued by the Homs for being [[VillainBeatingArtifact one of the few weapons truly effective against the dreaded Mechon]], and is used by Shulk to save the lives of his friends numerous times, thanks to its abilities to let him see the future and effectively warp reality to some degree. The blade, however, [[OnlyTheChosenMayWield cannot be wielded by just anyone]] and its continued use [[PowerDegeneration caused Dunban to lose all mobility in his right arm and nearly killed him]]. [[spoiler:It also turns out to be containing the soul of an EvilGod who intends to eradicate all life and recreate the world, and the only reason said god hadn't taken control of Shulk was because he was [[UnwittingPawn unknowingly following his plans]] for almost the entire story.]]
* ''VideoGame/XenobladeChronicles2'' doubles down on the trope. As part of a WhamEpisode, TheHeavy Malos breaks out his own Monado, complete with Monado Arts, some of which are the same arts Shulk used in the previous game. As it turns out, [[spoiler:Malos [[EmpathicWeapon IS the Monado]], his own weapon as an Aegis Blade. Pyra and Mythra, the other Aegis, also have distinctly Monado-like powers in their true Pneuma form as well. It turns out Monados themselves are extremely powerful, but also completely agnostic; it all comes down to the will of their users.]]
* ''VideoGame/YggdraUnion'' has the Gran Centurio. For centuries, it was believed to be a symbol of justice incarnate. However, it was eventually revealed to be a power generator that a manipulative fallen angel planned to use as the instrument of his revenge against the gods. It so happened to run on people's hatred and pain.
** The Gran Centurio also plays a small role in certain paths of ''VideoGame/BlazeUnion'' and ''VideoGame/YggdraUnison''.
[[/folder]]

[[folder:Visual Novels]]
* The aptly-named [[ShapedLikeItself Sword]] from the [[YuriGenre yuri]] [[VisualNovel VN]] ''VisualNovel/AoiShiro''. It was used to summon the divine storm that sunk the invading Mongol fleet in the past. The trope is downplayed as those with the qualifications to use it know that it's holy in the sense that "[[HolyIsNotSafe this item with terrible power is a property of the gods, do not touch]]," not "this is a weapon to battle evil." Also, it's not mentioned as such during the game itself, but it's ''the'' {{Kusanagi}}. It was originated from the [[SwirlyEnergyThingy Chaos]] that people in the past called {{Orochi}}, and will definitely, without exception, [[ArtifactOfDoom corrupt its user]].
* ''VisualNovel/FateStayNight''
** The wish-granting Holy Grail literally holds [[MadeOfEvil all the evil in the world]], and [[JackassGenie can only grant wishes through destruction]]. However, this is because the summoning of an eighth Servant, [[TheAntichrist Angra Mainyu (Avenger)]], during the Third Grail War inadvertently tainted the Grail -- it wasn't like that to begin with.
** In the third route of the VisualNovel, there's also Saber's Excalibur. For the first two [[MultipleEndings routes]], it is a holy "Sword of Promised Victory" that fires off a [[WaveMotionGun beam]] of [[LightIsGood bright light]]. Halfway through the third route, she is corrupted by the evil in the Grail [[spoiler:and becomes the newly villainous [[WoobieDestroyerOfWorlds Sakura]]'s Servant, Saber Alter]]. The switch from LawfulGood to LawfulEvil is accompanied by her sword turning into the [[PaintItBlack pitch-black]] "Excalibur Morgan" and firing off red/black beams. [[AllThereInTheManual This is explained]] as being due to Morgan Le Fay's hand in Excalibur's creation. It is still referred to as a holy sword, though.
** The prequel light novel and anime ''Literature/FateZero'' has [[spoiler:Arondight]], Berserker's actual weapon. It used to be a holy sword that would never be damaged, made to be wielded only by a perfect knight, but when her wielder [[spoiler:Lancelot]] went mad and used it to slay other [[spoiler:Knights of the Round]], it became a demonic sword filled with the madness and resentment of its master.
** The AlternateUniverse novel ''Literature/FateApocrypha'' has Clarent. Originally it was a sword of peace, made not for battle but for knighting and ceremonies, but was transformed into a demonic sword by Mordred's wanton hatred and used in rebellion against the lawful king, practically becoming a blood-based Excalibur. Also from same work is [[Literature/{{Nibelungenlied}} Balmung]], which is described as being a cursed holy blade due to it possessing attributes of [[Literature/TheSagaOfTheVolsungs Gram]], an actual demonic sword. It can be either a cursed sword or a holy sword depending on who wields it, with Siegfried being able to use it as a holy sword. ''VideoGame/FateGrandOrder'' later shows Balmung as wielded by his wife Kriemhild, and her quest for bloody revenge turned it from an ornate greatsword with a cross motif into a send-up to [[VideoGame/SoulCalibur Soul Edge]] capable of spewing dangerous curses.
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[[folder:Webcomics]]
* ''Webcomic/GirlGenius'': While it's actually a mace and his sword remained uncorrupted beyond its connection to him The Platonic Solid of the once good and now fabled king Andronicus Valois was twisted by his late Heterodyne allies into something that [[https://www.girlgeniusonline.com/comic.php?date=20170329 turns opposing forces into his undead minions.]]
* Inverted in ''Webcomic/{{Goblins}}'' by the Axe of Prissan. It was designed to generate an aura of evilness, so that any paladins who are aware of it would seek it out in order to destroy it. Once they touch the axe, it telepathically communicates to them that it's actually [[SealedEvilInACan being used to imprison a powerful demon who once tried to invade the Prime Material Plane]], and that a paladin must constantly use it to do good deeds, which will strengthen the wards of the demon's prison and prevent it from escaping. Furthermore, it is not only incapable of harming a paladin -- passing through them without leaving a wound -- but it also provides its wielder with a suit of magical plate mail, to better aid the above-mentioned good deeds.
** And then it's subverted all the way to the literal Hell. The legend was a ''lie''; the demon lord didn't reach the Material Plane nor was he defeated. The axe is a beacon forged in Hell that will allow him to travel ''to'' the Material Plane once it has stored enough energy by being used for evil acts. Paladins don't do anything to stop this as [[GreyAndGrayMorality nothing works in moral absolutes in the Goblins-verse]], and any deed deemed good can be perceived as sufficiently evil from another point of view. For example, the axe is being wielded by ''a goblin'' who repeatedly used it ''against humans'', which many would consider the modus operandi of the AlwaysChaoticEvil at a glance.
** Furthermore, the axe was forged by, and was supposed to be wielded by, ''Kore himself'', who's one of the posterboys for BlackAndWhiteInsanity thanks to the demons ''cursing him''. Talk about a deceptive weapon....
* The 13 Month Series from ''Webcomic/TowerOfGod'' are a set of powerful empathic weapons given to the [[AmazonBrigade Princesses of Jahad]]. Given what we've seen from Black March, they seem rather benign and weapons of good, but slowly information is trickling through to indicate otherwise; for instance, how the Eurasia family refused to be part of the Princess system any longer after their most powerful Princess, Eurasian Anne Jahad, went berserk after she received her sword. [[spoiler:It turns out King Jahad secretly cursed the weapons by having an AxCrazy woman DrivenByEnvy use DemonicPossession on any princess who uses more than one. King Jahad wants to forever remain on top of everyone else, but the 13 Months can be used to open the doors to the floors that even King Jahad could not climb, and he cursed the swords while setting up the unfair trials to keep every climber and ranker too busy killing and backstabbing one another to disrupt the system that keeps things that way]].
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[[folder:Western Animation]]
* The [[PowerCrystal rune stones]] in ''WesternAnimation/SheRaAndThePrincessesOfPower'', including She-Ra's [[TransformationTrinket Sword of Protection]], give the titular princesses powers they use to fight back [[TheEmpire the Horde]]. The only seemingly bad part about them is that the Horde were able to get one for their own use. [[spoiler:In truth, while the magic itself is benign and natural, [[AbusivePrecursors the First Ones]] created the sword to control She-Ra for their own ends and made the runestones siphon Etheria's magic into a superweapon that would wipe out life on Etheria and a good portion of the universe if used.]]
* ''WesternAnimation/StarVsTheForcesOfEvil'': When [[Characters/StarVsTheForcesOfEvilMarcoDiaz Marco Diaz]] wields Star's wand, it doesn't look as heroic as it does when Star wields it. Marco also has several connotations with the Blood Moon.
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