[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/mastersword_4298.jpg]]
[[caption-width-right:350: [[ItemGet Da Da Da DAAAH!]] ]]

->''For the king, for the land, for the mountains\\
[[GreenHillZone For the green valleys where dragons fly]]\\
[[LyricalShoehorn For the glory, the power to win the]] [[BigBad Black Lord]]\\
I will [[FetchQuest search for the]] [[InfinityPlusOneSword Emerald Sword!]]''
-->-- '''Music/RhapsodyOfFire''', "Emerald Sword"

The Sword of Plot Advancement is the offensive or defensive item that the central plot of the game revolves around, and whose collection by the player signifies that they are now capable of advancing to the end of the game. It thus marks the end of the [[ThreeActStructure Second Act]].

Alternatively, it may be gained at the beginning of the [[ThreeActStructure Second Act]], if it is important to game mechanics, and marks the beginning of the adventure proper.

Most of the time, since said sword acts as an AmplifierArtifact, it is the only AchillesHeel of the {{immortal|ity}} or NighInvulnerable BigBad. It may also be an example of a LegendaryWeapon.

It isn't strictly a MacGuffin (which is meaningless in and of itself), because after it is attained and the dramatic tension surrounding it dissipates, it is still useful within the game's combat mechanics.

It contrasts with the InfinityPlusOneSword, which is optional to the plot and is collected long after the protagonist ceases to require it. It is, however, somewhat of a headscratcher when said InfinityPlusOneSword (and even the InfinityMinusOneSword) is stronger; see PenultimateWeapon.

A sub-trope of both PlotCoupon and PlotCouponThatDoesSomething. Contrast ItWasAGift. See also SupernaturalAid. SisterTrope to SecondHourSuperpower and VillainBeatingArtifact.

----
!!Examples

[[foldercontrol]]

[[folder:Anime & Manga]]
* In an odd manga example, the Ten Commandments Sword from ''[[Manga/RaveMaster Groove Adventure RAVE]]'', is not only obtained early and one of two driving forces behind the main character's powers and abilities, but powers up not once, not twice, but NINE separate times. The last of these power-ups results in Ravelt, a Sword of Plot Advancement in its own right.
* ''Anime/RevolutionaryGirlUtena'': Utena is able to draw the sword of Dios from the Rose Bride starting in episode two, marking the beginning of her journey as a duelist. For the first arc of the series, this fantastic element seems fairly self-contained to Anthy; starting the second Black Rose arc, ''everyone'' can pull swords out of other people's chests! This ultimately culminates in Anthy having to draw a sword from Utena's breast, since Utena can no longer draw the sword of Dios from Anthy: Anthy draws the sword of Dios. As a bonus, these "soul swords" not only represent plot advancement (even if Utena can't see it) but also reflect character development and dynamics.
[[/folder]]

[[folder:Films -- Live-Action]]
* In ''Film/{{Thor}}'', Mj÷lnir serves this purpose.
* Narsil/And˙ril in ''Film/TheLordOfTheRings'': it symbolizes Aragorn's progression toward the throne of Gondor.
* In ''Franchise/StarWars: Film/ANewHope'', receiving his father's lightsaber is part of Luke's CallToAdventure near the end of act 1.
[[/folder]]

[[folder:Gamebooks]]
* The Sommerswerd in the second ''Literature/LoneWolf'' gamebook ''Fire on the Water'', which is also an InfinityPlusOneSword that can be used in subsequent books in the series.
[[/folder]]

[[folder:Literature]]
* In ''Literature/UnLunDun'', the [=UnGun=].
* Creator/WaltDisney's First Pen in ''Literature/TheKingdomKeepers''
* ''Literature/TheSwordOfShannaraTrilogy'' has the sword mentioned in the title.
* Kosall in ''Literature/TheActsOfCaine''
* The Sword of the Lady in the Literature/{{Emberverse}}.
* The ''Literature/SwordOfTruth'' has the title sword, which is magically-imbued and has no equal. Richard gets it in like, the third chapter. Of the first book. Of a series of eleven doorstops. In fact, it becomes so associated with him and he actually reflexively reaches for it even when he doesn't have it, and other characters associate it with him personally. He eventually doesn't need it to kick twelve kinds of ass, but still prefers it to regular swords.
* The orb of Aldur from ''Literature/TheBelgariad'' seems like a MacGuffin until the hero picks it up near the end of the series and starts whomping all kinds of ass with it (and his signature BFS, of course, which is so heavy that the orb has to "carry" it for him). In the follow-up series, it becomes useful in all kinds of other ways throughout. Considering the sword was forged from two fallen stars, it was enormously heavy. The original creator was even advised to remember the weight, because if the orb were removed, and he were holding the sword, he'd likely break his wrist.
* In ''Literature/TheWheelOfTime'' the one who can wield the crystal sword Callandor is the Dragon Reborn -- the chosen one. The main character acquires it in the third book and then announces his station to the world. "The only one who can wield it" is not precisely true. He was the only one who could pick it up without dying, yes, but as soon as he did, the magic protecting it was gone. After he left Callandor behind at the Stone of Tear, Morgaine berated him for leaving the third most powerful magical object in existence lying around for his enemies to steal. It's also such a strong AmplifierArtifact that using it as a sword is a complete waste of its potential.
* ''Literature/HarryPotterAndTheDeathlyHallows'' is focused on Harry, Ron and Hermione's trying to find/destroy Voldemort's [[SoulJar Horcruxes]]. The quest only takes off after they discover where Gryffindor's sword is hidden.
* The ''Literature/MortalInstruments'' series has several, two of them literal.
** The Mortal Cup is the focus of the first few novels. It is part of a set with the Mortal Sword and the Mortal Mirror.
** "Glorious", the sword of ArchangelMichael.
[[/folder]]

[[folder:Live-Action TV]]
* Several Heisei ''Franchise/KamenRider'' series have the main character gain his SuperMode via the acquisition of a unique and powerful sword, hence the FanNickname "[=SwordGrade=]" ('''sword''' + up'''grade'''). Examples include Faiz's Faiz Blaster (doubles as a {{BFG}}!), Hibiki's Armed Saber, and Den-O's [=DenKamen=] Sword; Kabuto's Perfect Zecter and Kiva's Zanvat Sword are typically counted despite coming ''after'' the Rider got his SuperMode. The rest [[note]]Agito [[ShiningGoodness Shining Form]], Blade King Form, Double CJX, OOO [=PuToTyra=], Fourze Cosmic, and Wizard Infinity[[/note]] have swords (or in OOO and Wizard's cases, axes) that are part of their powers, rather than the source of them. The stand-outs are Decade, who uses the same weapon in all his forms, and Gaim, whose penultimate form gets the unique weapon (though his final form can also use it due to being a WalkingArmory).
[[/folder]]

[[folder:Myths & Religion]]
* KingArthur getting the Sword in the Stone and Excalibur (which may or may not be the same -- Arthurian canon can be confusing) are important steps in his rise to power, and Excalibur is his main weapon through pretty much the entirety of his life. Excalibur's sheath, arguably the more valuable artifact, provided magical protection that safeguarded Arthur and ensured Camelot's prosperity. The loss of the sheath kicks off Arthur's and Camelot's eventual downfall.
* NorseMythology: In ''Literature/VolsungaSaga'', Sigmund can only accomplish his vengeance on Siggeir after his sister Signy gives him the sword of Odin. Much later, Sigmund's son Sigurd receives the shards of the same sword from his mother, which he has then reforged into Gram, the weapon with which he goes on to avenge his father and kill the dragon Fafnir.
[[/folder]]

[[folder:Pinball]]
* The player begins with a scimitar in ''Pinball/TalesOfTheArabianNights'', but must enchant it with seven [[PowerCrystal magic gems]] before he can confront the evil genie of the game.
[[/folder]]

[[folder:Tabletop Games]]
* In early editions of ''TabletopGame/DungeonsAndDragons'', Artifacts were meant to be this. Rather than just supremely powerful magic items (which, admittedly, they were), every Artifact had a backstory and usually some kind of curse or other condition that made life... "interesting" for anyone who ended up with one in their possession. The Hand and Eye of Vecna, for example, slowly drove their bearers to recreate Vecna's fallen empire (with plenty of tyranny along the way). Or digging up pieces of the Rod of Seven Parts caught the attention of various powerful demons since it was used to bind the essence of their greatest lord. An Artifact was something that entire campaigns were meant to turn around, and were never meant to be treated as just another step up in power for a PlayerCharacter.
[[/folder]]

[[folder:Video Games]]
* ''Franchise/TheLegendOfZelda''
** The Master Sword in several ''Zelda'' games, starting with ''VideoGame/TheLegendOfZeldaALinkToThePast''.
** Yet it's sometimes a different sword, such as the Phantom Sword in ''VideoGame/TheLegendOfZeldaPhantomHourglass''. And other times, such as in the original ''VideoGame/TheLegendOfZelda'' game and ''VideoGame/TheLegendOfZeldaLinksAwakening'', the sword upgrade has nothing to do with the plot.
** Generally, if Ganon's in the game, it'll be the Master Sword. The side-stories substitute their own upgraded blades.
** ''VideoGame/TheLegendOfZeldaOcarinaOfTime'' is one such game, in which the Master Sword comes one-third of the way through the game's dungeons and triggers a seven-year TimeSkip.
* And the Zelda clone ''VideoGame/{{Alundra}}'' gives you your initial weapons in this fashion. You need them to solve puzzles just like the items in Zelda games.
* In ''VideoGame/ArcTheLadTwilightOfTheSpirits'', Darc picks up a nameless sword before the final boss fight of his first story unlike most exaples it is your only weapon throught the game and changes his fighting style to now include techniques and slashes
* ''VideoGame/AncientDomainsOfMystery'' has the five [[PlotCoupon Chaos orbs]] which can be worn one at a time for a stat boost, or invoked to use their special powers (at the cost of advancing the PC's [[TheCorruption corruption]]).
* The Vampire Killer in ''/VideoGame/CastlevaniaPortraitOfRuin''. An unusual case, since the Vampire Killer is A) a whip and B) the hero has it already. The real focus is the quest to unseal it and use it to defeat {{Dracula}}, but the hero is warned that if it's used too much [[ArtifactOfDoom it'll kill him]] the same way it killed his father. There's no ingame effect representing this, but it's hinted it takes longer than one would spend tramping around Castlevania for the effect to kick in.
* The Masamune from ''VideoGame/ChronoTrigger'' is an interesting case. It's required to advance the plot, but since it's just used at the halfway point, it gets overshadowed fairly quickly by other weapons Frog can just buy. However, one sidequest can empower it to its full potential, making it both this and an InfinityPlusOneSword at different intervals.
* The eponymous ''VideoGame/{{Crystalis}}'', though you acquire it right before the final boss battle, after entering the PointOfNoReturn.
* The eponymous ''VideoGame/{{Daikatana}}'', even though most people couldn't even find the sword for about three years, and it was ''less'' useful than a gun... although more useful than your sidekicks.
* In [[VideoGame/{{Doom}} Doom 3]], on your first journey through Hell, you find the "Praeleanthor", a.k.a. "The Soulcube". It was apparently being used as a portal between Hell and Mars, but it also functions as a weapon that can [[OneHitKill one-shot]] every non-boss enemy in the game, including the [[DegradedBoss Vagaries and Hell Knights]]. It's also the only way to kill the Cyberdemon, the only creature you will find that can withstand multiple Soulcube hits (or any at all, besides Sabaoth).
* ''VideoGame/DragonQuest''
** [[AncestralWeapon Erdrick/Loto's Sword]] in ''VideoGame/DragonQuestI'' and next [[ContinuityNod two sequels]]. The Zenith Sword in IV through VI, though with a different name and color in the last.
** In ''VideoGame/DragonQuestIII'', an astoundingly significant portion of the game is spent trying to get the Gaia Sword, just so that it can open a path to a MacGuffin. This sequence involves getting a ship, finding a place you can't go with the ship, finding a mirror that you can use to get a staff that you can trade to get a bone that you can use to get a locket that you can use to unlock the place you can't go with the ship. If you're following the manual, this will take you from level 20 all the way to level 34, in a game which recommends you be level 40 to fight the end boss. And that's just to get the Gaia Sword. The only purpose of the sword is to get you to the last of six orbs, five of which you picked up while trying to get the Gaia Sword. Ugh. You open up the path to the last orb by throwing the Gaia Sword into a volcano. There aren't even any bosses between getting it and getting rid of it.
** And in ''VideoGame/DragonQuestIV'', there's an entire set to collect, with the Zenithian Armor, Helmet and Shield to match the inevitable Sword.
** In ''VideoGame/DragonQuestV'', you are required to do two long dungeons and marry a girl in order to get a plot-advancing shield...and you can't even use the damn thing until later in the game. [[spoiler: In fact, ''you'' can't use it at all. For once in a DQ game, the main character is ''not'' TheChosenOne.]]
** And again in ''VideoGame/DragonQuestVII'', with the Aquagon sword. But in a twist, you get this sword before getting any hint to its significance. Sure, the king of Coastal talked it up as their legendary treasure... but you also heard that same speech earlier in the game about a simple Bug knife. But the Aquagon comes back later, first [[spoiler:proving to Sharkeye that the heroes are telling the truth]], and then later [[spoiler: being the key to reviving the Aqua Spirit and freeing the world from darkness]].
* Despite not being a tangible object, the great power that Ness discovers in himself near the end of ''VideoGame/EarthBound'' fits this trope.
* ''VideoGame/EccoTheDolphin'' receives the power to Advance the Plot from the Asterite in the penultimate sections of the first and second games. The fact that it eliminates the need to breathe is a small bonus.
* ''Franchise/TheElderScrolls''
** ''VideoGame/TheElderScrollsIIIMorrowind'' has the hammer Sunder, the sword Keening and the gauntlet Wraithguard that you need to use together to defeat Dagoth Ur. Interesting thing is that they don't need to be used against him personally. You're supposed to strike the Heart of Lorkhan once with Sunder and then three times with Keening to kill him.
** Its expansion ''Tribunal'' not only asks you to find but to repair and relight [[AwesomeButImpractical (yes it is a flaming sword)]] the blade Trueflame. It's important to the plot. Really. It ''is'' important to Almalexia and getting her to reveal the fact that [[spoiler:she's gone batshit crazy and thinks she needs to kill the Nerevarine, aka, you in order to maintain her god status. Getting the sword is probably meant to prove you're Nerevar's reincarnation]]. One of the people who help you restore the blade points out that the flames are pretty much for decoration, and have absolutely no effect on its performance as a weapon. Looks pretty, though.\\\
It is still a pretty powerful weapon. It is the most powerful artifact sword in the game. This means that it lacks the massive enchantments that are possible with player enchanted weapons. It does only 30 fire damage as opposed to the 300 possible with a top level sword and soul gem, as well as having a slow swung. It is one handed though which allows one to use a shield, which is at the very least an additional enchantment slot. Having a weapon do 300 magic damage sure can suck when you meet high level enemies that reflect/absorb magic.
** ''An Elder Scrolls Legend: Battlespire'' has the Moon Reiver, the only sword that can hurt the final boss, Mehrunes Dagon.
* ''VideoGame/{{Fable}}''
** The Sword of Aeons in ''VideoGame/FableI'' if you're evil, or Avo's Tear if you're good, although Avo's Tear only appears in the expanded re-release of ''Fable''. This should be in '''infinity + 1'' section as you get it after you beat the game and no enemy demands it to be killed. It averts the InfinityPlusOneSword territory in the expanded ''Lost Chapters'' version of the game, since you easily have 5-10 hours of remaining gameplay to go through after you acquire the swords. And since a quarter of the game was spent attempting to stop [[spoiler:Jack]] from acquiring the blade, it is still plot relevant. ''Lost Chapters'' also nerfs the Sword Of Aeons (and introduces Avo's Tear as its counterpart).
** Also the [[spoiler:music box from the beginning]] in ''VideoGame/FableII'' sort-of becomes this trope, although its not really a sword, and [[spoiler:you don't really get to use it in any battle, you just hold down A in a cut scene to use its magic on the big baddie of the game]]
** Scimitar of Baron slaying +3 anyone?
* ''Franchise/FinalFantasy''
** The Ultima spell in ''VideoGame/FinalFantasyII''.
** ''VideoGame/FinalFantasyIV'' has Cecil receive the Legend sword (or Mythgraven sword, for the remake) when he becomes a paladin. Though it can eventually be reforged into the Excalibur, second (or third, depending on the version) best sword in the game.
** Also, the twelve legendary weapons in ''VideoGame/FinalFantasyV''. For the last portion of the game, Ghido entrusts you to collect four tablets in order to unseal the weapons, three at a time. Almost averted, as the weapons are incredibly powerful and yield neat bonuses when you equip them. However, the final dungeon includes ''even more'' powerful weapons, so much that most of the legendary weapons are overshadowed. The ones that don't? Weapons you wont ever use, like bells and whips.
** ''VideoGame/CrisisCore: Final Fantasy VII'' has Zack obtain the almighty Buster Sword after [[spoiler:he is forced to defeat his mentor, Angeal.]] It doesn't do anything to his stats, but its acquisition is mandatory. Interestingly, by the time of ''Final Fantasy VII'', the Buster Sword is Cloud's ''weakest'' sword.
** ''VideoGame/FinalFantasyXII'' gives you ''two'' such swords, with opposite functions, and a major part of the plot is the heroine deciding which sword to use. [[AwesomeButImpractical They have the exact same stats in battle, and completely suck.]] In fact, the only reason you would ever use one of them is on a SelfImposedChallenge, as they are the only weapons in the game that don't require licenses to use.
* ''Franchise/FireEmblem''
** In the first game and it's remakes, a lot of the plot is involves Gharnef stealing the Falchion early on and Marth reclaiming it near the end of the game. Of course, due to the game mechanics, it's entirely possible to skip out in getting it and finish the game without it. Its advantages are infinite durability and either complete immunity from any non-dragon attacks (in the first game) or effectiveness against dragons (in the remakes), as well as being able to heal HP but in terms of power there are several weapons that overshadow it...which you get earlier on as well as the ability to forge ordinary weapons to give them more power in the DS remake.
** In the fourth game, ''[[VideoGame/FireEmblemJugdral Genealogy of the Holy War]]'', there's the Tyrfing. You hear a couple passes at this legendary sword in the first generation, but nothing important, then early in Chapter 5, [[ATasteOfPower you're given it -- and it's quite powerful, but you don't have it long for certain reasons.]] [[spoiler: Your entire army is killed following Chapter 5.]] Come Chapter 6, however, which starts with the main character's son, Seliph, Tyrfing has become this -- an all important sword that will make him a BadAss that can kick TheEmpire in the nuts, once he gets it, that is. Unlike most other examples however, this IS Seliph's best weapon. (And like the Falchion, it's possible to miss Tyrfing both times).
* ''TabletopGame/ForgottenRealms: Demon Stone'' has the silver sword of the Githyanki, which is needed to kill the [[BigBad Slaad Lord]].
* ''VideoGame/{{Grandia}}''
** The Spirit Sword of the original ''Grandia''.
** ''VideoGame/GrandiaII'' features locating the Granasaber, a sword that fell to earth during a battle between two Gods, as a major part of the game's second act. [[spoiler: Subverted as it turns out to be a spacecraft, not a sword at all, and then ''played straight'' at the end of the game when the hero actually does acquire a sword called the Granasaber, capable of harming the evil God rampaging across the world.]]
* ''Franchise/{{Lufia}}''
** ''VideoGame/LufiaAndTheFortressOfDoom'' and ''VideoGame/LufiaTheLegendReturns'' have the Dual Blade, a sword wielded by the hero's ancestor, Maxim, which is the only weapon capable of harming the deity-like Sinistrals terrorizing the world. A substantial portion of both games revolve around mounting an expedition to recover this sword from the site of your ancestor's final battle.
** In the prequel ''VideoGame/LufiaIIRiseOfTheSinistrals'', where you play as Maxim, he proves his worthiness to wield the Dual Blade by forcibly taking it from the BigBad himself near the end of the game.
* ''VideoGame/WorldOfMana''
** The Sword of Mana in many of the ''Mana'' series of games. It often has rusted or the like over the years, and requires repairs through the course of the plot. Sometimes these are incremental, and sometimes these happen all at once. The final repair inevitably turns it into the InfinityPlusOneSword.
** Strangely, in some games (''VideoGame/SwordOfMana'', ''VideoGame/LegendOfMana'', ''VideoGame/SeikenDensetsu3'') in the series it can never be equipped.
** And ''VideoGame/ChildrenOfMana''...come to think of it, is there any game other than ''VideoGame/SecretOfMana'' and the original ''VideoGame/FinalFantasyAdventure'' where it ''can'' be equipped?
** Even in ''Secret of Mana'', while the sword you equip is the Sword of Mana, it does not become ''the'' Sword of mana until magically imbued by your teammates during the last battle, or through a glitch. Otherwise the best you can use is the next level below.
** Basically in games where you can wield it, you only get the sword literally 5 seconds from or already engaged in the end fight. In installments where you gain it earlier, nobody --including heroes who look tailor designed for the role-- is smart enough to pick it up as a weapon. Not even in the game ''named after the sword.'' Which, according to the series's Japanese name, would be ''every game''.
** In ''VideoGame/SecretOfMana,'' you have the Sword of Mana from start to finish. Even if its not at full power, it is still the Sword of Mana, no other sword can replace it.
%%
%% The "Metroid" games don't count because the "central plots" of all of them have little or nothing to do with the items Samus collects.
%%
* ''VideoGame/NeverwinterNights''
** The Sword of Gith in ''VideoGame/NeverwinterNights2''.
** Regaining the now even better Sword of Gith in the ''Mask of the Betrayer'' expansion.
* About three-quarters through the Xbox ''VideoGame/NinjaGaiden'' and the Xbox 360 ''VideoGame/NinjaGaiden II'', Ryu gets to combine the Dragon Sword with the Eye of the Dragon to form the True Dragon Sword that is supposedly needed to defeat the BigBad.
* ''VideoGame/PhantasyStar''
** Orakio's Sword in ''VideoGame/PhantasyStarIII: Generations of Doom''.
** And Elsydeon in ''VideoGame/PhantasyStarIV: End of the Milennium''; with the bonus multiplier against Evil-type creatures and a chance of getting the 'Holy Word' effect, this also makes it the InfinityPlusOneSword.
** Two easier-to-miss ones, also from ''Phantasy Star IV'', are the Eclipse Torch and the Psycho Wand. The former is used to burn away evil trees blocking your path, and the other was needed to break TheDragon's otherwise impenetrable barrier. The Torch can be used as a Holy attack item in battle, and the Wand can be used to break barriers on the few enemies that use them, throughout the entire game.
* ''Franchise/{{Pokemon}}''
** The boxart-featured {{Mons}} (Groudon, Kyogre, and Rayquaza for ''VideoGame/PokemonRubyAndSapphire'' and Palkia, Dialga, and Giratina ''VideoGame/PokemonDiamondAndPearl'') must be encountered to advance the plot (though Rayquaza doesn't have to be fought right away; it only needs to be approached), though this only applies to the one on the box of the game being played. Suicune from [[VideoGame/PokemonGoldAndSilver the second generation]] was like this as well (again, only for the game it appears on the box for, in this case, ''Crystal''). The ones from the other second generation games (Lugia and Ho-Oh) become this in their fourth-generation remakes (which add a Suicune subplot as well), despite being optional except for OneHundredPercentCompletion in the original versions of the games (the one on the box of the game being played could merely be encountered earlier the original versions of the games, with the other game's mascot being available later).
** And in ''VideoGame/PokemonBlackAndWhite'', you are [[spoiler: forced to catch (not defeat) your version legendary]] before you're allowed to battle [[spoiler: N and his legendary]].
** The above occurs again in ''VideoGame/PokemonXAndY'' where you must [[spoiler: capture your version legendary]] before you can battle [[spoiler: Flare Boss Lysandre]].
* ''Realmz''
** In the scenario ''Assault on Giant Mountain'', you must acquire the powerful greatsword Giant Slayer in order to proceed...but the reason it's necessary isn't so that you can wield it, but because the BigBad's fortress is magically inaccessible until you destroy it on the Anvil of Pain. This is [[PlayerPunch difficult to do]] since it's probably become your fighter's favorite weapon.
** This trope pops up in other scenarios too, like the obsidian scimitars from ''Destroy the Necronomicon'' and the Spear of Light from ''Griloch's Revenge''.
* In ''VideoGame/SaGa3'', the Mystic Swords are the only weapons capable of damaging the BigBad.
* ''VideoGame/ShadowKeep'' required you to find the Black Sword, the only weapon that could harm the evil overlord (and another item, the only thing that can keep him from killing you in one blow.)
* The ''Franchise/ShiningSeries'' is very fond of this trope;
** ''VideoGame/ShiningForce'' you combine the Sword of Light and the Sword of Darkness to make the [[YinYangBomb Chaos Breaker]].
** ''Shining Force II'' has both the Achilles Sword and the Force Sword (which, as revealed in ''[[NoExportForYou Shining Force Gaiden: Final Conflict]]'', is the Chaos Breaker mentioned above, just renamed). Oddly enough however, in the second game it looked more like a [[StarWars lightsaber]] ([[IncrediblyLamePun get it?]]).
** ''Shining Force The Sword of Hajya'' has the titular sword be required to deal the first swing to the BigBad.
** Arthur gets one in ''VideoGame/ShiningTheHolyArk'' which is required to break the barriers surrounding TheVeryDefinitelyFinalDungeon.
* The "Force weapons" in both ''VideoGame/StarOcean1'' and [[VideoGame/StarOceanTheSecondStory its sequel]], though their importance to the plot is only revealed just before you get them.
* Happens all the time in ''VideoGame/SuperRobotWars'', and sometimes inverted when its a machine you have to ''destroy''. Memorable examples include Ryukooh and Koryuoh, Getter Shin Dragon from SRW Destiny, the R-Series in Original Generation 1 and the enemy unit Judecca.
* ''Franchise/TalesSeries''
** The Eternal Sword in ''VideoGame/TalesOfPhantasia'' and ''VideoGame/TalesOfSymphonia''. In other games it becomes the InfinityPlusOneSword.
** The Key of Lorelei in ''VideoGame/TalesOfTheAbyss''.
** Dein Nomos in ''VideoGame/TalesOfVesperia'' is a slight subversion as you get it about 2/3 into the game, it's far from being Yuri's ultimate weapon ([[spoiler:a replica of it is stronger]]) and you lose it after a few dungeons. In the [=PS3=] version [[spoiler:you get Brave Vesperia No. 2 (the device the party plans to use to destroy the Adephagos), as a weapon before the final dungeon. It allows Yuri to use his second Mystic Arte.]]
** Wahrheit in ''VideoGame/TalesOfHearts'' - after it's been converted to the GlobalAirship Lianheit. (It's the personal weapon of a nonplayable character.)
* ''Franchise/TombRaider''
** [[spoiler:Excalibur]] in ''Tomb Raider: Legend''. You only get to use it for a brief escape scene and a boss before the game abruptly ends though.
** In ''Underworld'', you also get your hands on [[spoiler:Thor's Hammer]].
* ''Franchise/{{Ultima}}''
** The original Black Sword in ''VideoGame/UltimaVII''. The Black Sword is only needed to complete the ''Forge of Virtue'' expansion, not the main game. Since the expansion is entirely optional, this may not count. In VII part 2 (''The Serpent Isle''), you start the game with the sword (implying the Avatar did complete the ''Forge'' expansion), promptly lose it, and need to recover it in order to get packed off to the world of ''Pagan''.
** The Mystic Arms in ''VideoGame/UltimaIV''. You don't need the Mystic Arms to complete ''Ultima IV''. The game claims only Mystic Arms work in the Stygian Abyss but in fact any magic weapon will work.
** The Sword of Justice from ''VideoGame/UltimaUnderworld'' probably counts, as it's one of the 8 items needed to complete the game and is a very good weapon (the only unbreakable one as well). Subverted in that completing the game requires you to ''destroy'' the sword (along with the other items). Trying to kill the BigBad with it is pointless.
* In ''VideoGame/UnlimitedSaGa'' you have at some point to collect the elemental gears in Laura's quest, some of the best equipment you'll ever get in the game. [[spoiler: Too bad that you don't get to keep them for the end of the game.]]
* The title sword in the first ''VideoGame/VandalHearts''; in the sequel, it is optional for the overall game, but necessary for the best ending.
* Broaste's teddy bear in ''VideoGame/WanderingHamster''. Yeah, it's THAT kind of RPG.
* The Runeblade Frostmourne from ''VideoGame/WarcraftIII'' is vital to defeating Mal'Ganis, but also grants a combat boost when Arthas first gets it. Annoyingly, this boost goes away when you start the next campaign, and from the on its power is only shown in {{cutscene|PowerToTheMax}}s, though it theoretically responsible for Arthas' death knight powers as well.
* ''VideoGame/{{Diablo}}''
** First ''Diablo'' has Lazarus's Staff. It's not a weapon you can equip, but you need to give the staff to Cain so the portal to Lazarus' lair opens afterwards.
** ''Diablo II''; One's an epic staff (Horadric Staff); the other is an epic mace (Khalim's Will). Your forced to give up both to foward the plot. The staff opens the true Tomb of Tal Rasha in Act 2 and Khalim's Will opens the stairwell to Mephisto's Durace of Hate in Act 3.
** Act 1 of ''VideoGame/DiabloIII'' has you running around collecting the pieces of an angel's mighty sword.
* The Mavin Sword in the D.W. Bradley game ''VideoGame/WizardsAndWarriors'', acquired just before the third act of the game, and it's quite a powerful sword, in addition to supposedly being the only weapon capable of harming the BigBad (there's actually a second weapon able to harm the Big Bad, [[GuideDangIt not that you're ever told it can do so]]).
* Happens twice in ''VideoGame/{{Zeliard}}''. The Knight's Sword is the first sword that's (at that point) only available as a 'quest' rather than simply buying as an upgrade, and you're told it's essential to beat that level's boss (apparently, overly keen players have showed that it's not). Near the end, you're supposed to find the Faery Flame Sword in a fairly similar manner.
* The [[HumongousMecha Gears and Omnigears]] of ''VideoGame/{{Xenogears}}'' are required to fight many bosses and complete many dungeons. Citan's sword, [[KatanasAreJustBetter cool as it is]], is not all that plot-relevant.
* In the original ''VideoGame/DevilMayCry'', after Dante defeats the BlackKnight Nelo Angelo for the last time the knight drops an amulet, identical to Dante's own. [[spoiler:It turns out that Nelo Angelo was really Vergil, Dante's JerkAss twin brother [[RivalTurnedEvil who was forced into Mundus's service after the events of DMC 3]].]] Anyhoo, the amulet combines with Dante's into the Perfect Amulet, which is part of the way to open a Portal to [[BonusLevelOfHell Mundus's world]] as kick his ass. Additionally, exposure to the amulet unlocks the true power of the Force Edge, Dante's starting sword; it becomes much stronger as Sparda. The Sparda is the only weapon Dante can use against Mundus's first two forms anyways.
* ''VideoGame/RogueGalaxy'' features an equippable weapon crafted from {{plot coupon}}s in the penultimate dungeon, which goes away after the first two of ten final boss battles, a {{BFS}} Jaster automatically gains and equips for the VERY final battle, and the Desert Seeker Jaster gains at the beginning of the game (which can evolve into one of his strongest weapons).
* The eponymous VideoGame/{{Valis}} Sword.
* The Firestaff in ''VideoGame/TheNamelessMod''. It's not really a sword (it sets things on fire instead), but it has administrative powers and thus is very important to the plot.
* In ''BlackSigil'', [[TheHero Kairu]] is entrusted [[{{BFS}} the Sword of Averay]] by his adopted father, Duke Averay. It eventually becomes critical to the plot involving the SealedEvilInACan.
* The first ''VideoGame/{{Gothic}}'' has the sword Urizel, which is one of the few things that can harm the last [[NinjaPirateZombieRobot undead orc shaman]]. (Spellcasters can have it turned into the "Wave of Death" rune, which is the only ''other'' thing capable of harming said enemy.) Note that you find it well before the end of the game (and have to empower it in a spectacular fashion), so you get to enjoy its sheer killing power on many regular enemies as well. In a more strict interpretation, you have to obtain the shamans' five swords, which are too damaged to be of regular use, but are vital to defeating the BigBad right at the end.
* ''VideoGame/WildArms2'' has the Argetlahm, which subverts this trope before playing it straight. Its first appearance makes it obvious that you won't obtain it until the end of the game, but you're quickly forced into a situation where it's absorbed by the hero to turn a DemonicPossession into a mere SuperpoweredEvilSide. [[spoiler:In the end, said demon takes over again, but the protagonist is able to draw the sword for real while trapped inside his own soul.]]
* The Silver/Cleria Sword in ''VideoGame/{{Ys}} I and II''. In Book 1, you get it right before TheVeryDefinitelyFinalDungeon, and there is an InfinityPlusOneSword in said dungeon, but that doesn't work against Dark Fact. In ''Book II'', it is the InfinityPlusOneSword, and you obtain it just before fighting the BigBad Darm. In ''Ys Origin'' it's the same sword as in ''Book I'', but you get it in a cutscene after defeating the penultimate boss and before facing the final boss in one route. In ''Ys IV: The Dawn of Ys'', you start with the Cleria Equipment, but lose it shortly after, to regain it near the end of the game. ''Ys: The Ark of Napishtim'', the sixth game in the series, has only three swords (which can be upgraded) and all of them are relevant to the plot. In ''Ys: Oath in Felghana'' this sword and the InfinityPlusOneSword are the same: it's obtained automatically before the final dungeon, and is the only weapon capable of breaking the barrier spell used by the penultimate boss.
* Leo's Sword (that's the name of the sword itself) is this in ''VideoGame/AgarestSenki''. Seemingly only used in [[CutscenePowerToTheMax cut scenes,]] when you [[spoiler: finally get to the True Ending path, not only do you ''finally'' get to use it, but when you upgrade the sword itself, the stats are through the roof! It's definitely not the most powerful sword, but it's still up there.]] [[FridgeLogic Makes you wonder why you could not use it in gameplay even though Leo has it in his hand and could have prevented his death]] ''[[GameplayAndStorySegregation all the way back from the start.]]''
* ''VideoGame/GoldenSunDarkDawn''
** The Sol Blade, which is required to [[spoiler:open the gate to the Apollo Lens's control room]]. It's also used to access certain dungeons.
** On the subject of the Apollo Sanctum, [[spoiler:the pieces of the Umbra gear project a barrier of darkness to protect their wearer from the Sanctum's intense light. In order to enter, you need the full suit, as the protection provided by each individual piece is hardly sufficient to keep you from frying. Further historical information suggests that ancestral beastmen wore similar suits during the Sanctum's construction. Even if the powerful unleashes and the heightened elemental Resistance weren't incentive enough, you can't end the Grave Eclipse until Sveta's decked out entirely.]]
* The Ultragunner in ''VideoGame/VanguardBandits''.
* The Dragon Slayer in ''VideoGame/LegacyOfTheWizard'' and ''VideoGame/{{Faxanadu}}''.
* The Hawke's Key in the ''VideoGame/DragonAgeII'' "Legacy" {{DLC}}. You obtain it fairly early in the quest, and it is vital to progressing through the dungeon. Since it's leveled like most of the equipment in the game it will be powerful when you get it but it will be eventually obsolete.
* In ''VideoGame/{{Mantra}}'', the main plot coupons (the eponymous five Mantras) are magic scrolls. Each one gives you the ability to perform a specific type of attack that has an [[ElementalRockPaperScissors elemental damage type]]. They're useful in combat with normal enemies and bosses, and they're also necessary to destroy barriers which are only vulnerable to specific elemental damage types, so that you must acquire the appropriate Mantra in order to advance to the next area.
* The Monado from ''VideoGame/{{Xenoblade}}''. Almost everything in the game's plot is done in to, by, or in response to it. It's also the only weapon [[TheHero Shulk]] can use once he obtains it, and its strength scales with his level to keep it from ever becoming obsolete.
* The Magic Sword in ''VideoGame/HyperdimensionNeptuniaMk2'' where it has been said that it can demolish the most powerful evil in existence. There's just one problem. [[spoiler: You're gonna have to do the [[PlayerPunch worst]] [[TheBadGuyWins ending]] [[TearJerker of]] [[NiceJobBreakingItHero that]] [[NightmareFuel game]] to even obtain it in a NewGamePlus.]]
* Splendor in ''VideoGame/DeadlyTowers''.
* ''VideoGame/TheLordOfTheRingsOnline''
** A system of Legendary Item advancement is introduced in its first expansion, ''Mines of Moria''. Until the player receives his Legendary weapon and proves that he can operate with it (reforge, slot relics, apply titles etc) he cannot advance the Main Storyline and cannot pass the Doors of Moria.
** An example from the original book is Narsil / And˙ril. Turns out a special mineral is required to reforge such an epic sword and the player is send on a quest to get a piece of it (which composes the longest non-epic quest chain in the game by the way). Until you finish it, Narsil cannot be reforged and the Fellowship cannot leave Rivendell.
* ''VideoGame/FalloutNewVegas'' features this in the ''Old World Blues'' expansion -- the Think Tank wants you to collect three items to defeat Dr. Mobius -- a frequency to disable force fields, an antenna to amplify the frequency, and a stealth suit to sneak into Dr. Mobius's lair. [[spoiler: It turns out that Dr. Mobius wanted you to [[NiceJobBreakingItHero bring all that stuff to him instead]] -- [[SubvertedTrope to help you get your brain back in your skull]]. ]] That said, even after the quest, all three items are quite useful when exploring the Mojave.
* One of the last things to do in ''VideoGame/MightAndMagic VI'' before attacking the Kreegan Hive is to acquire blasters and the skill to use them. Unusual in that there are ''several'' blasters to be found in the associated dungeon, significantly more than the four characters you have, and in that there are upgraded versions deeper in the dungeon that count as blasters for all important purposes, but they can only be found in that dungeon, and getting at least one is absolutely necessary to finishing the game (for more than one reason if you want to finish the game without a NonstandardGameOver)
* The Knight's equipment in ''VideoGame/GreatGreed''.
* In ''VideoGame/LunarTheSilverStar'', Alex becomes a Dragonmaster and becomes able to approach the Magic Emperor once he obtains the Althena Sword. The other Dragon Items also play a big part in advancing the plot, but this is the last of them.
* The second ''VideoGame/GoldenSun'' game has the Trident of Ankohl, which is only really ''needed'' to break [[BeefGate Poseidon]]'s forcefield. However, it's useful for the rest of the game because the equipment system treats it as a usable accessory rather than a weapon, giving the bearer 20 Mercury resistance and a Jupiter-aligned attack (based on the attack stat, rather than the Jupiter power stat) for free.
* The Keyblade from ''Franchise/KingdomHearts'', which changes its outward form and power throughout the game but has essentially the same plot-important abilities. It's also an EmpathicWeapon .
* Raziel gaining the Soul Reaver following the second boss-battle of ''VideoGame/LegacyOfKain: Soul Reaver''.
* In ''VideoGame/HeavenlySword'', the eponymous Heavenly Sword.
* ''Franchise/PrinceOfPersia''
** Both ''VideoGame/PrinceOfPersiaTheSandsOfTime'' and ''VideoGame/PrinceOfPersiaTheTwoThrones'' have the Prince gaining the Dagger of Time early on, allowing access to the time control gameplay that is the series selling point. In an interesting partial subversion, you generally get the weapon very early in these games (or start with it) and the idea is to get rid of it properly.\\\
Another interesting point about ''The Sands of Time'' is that you actually get to use the InfinityPlusOneSword for awhile (after [[spoiler:Farah absconds with your main sword and the Dagger]]) that can shred enemies in a single blow without having to absorb them into sand (though you do lose your time flipping powers in the process so it waltzes between this InfinityMinusOneSword status). However, the end of the game [[spoiler:rewinds everything back to things right before the events of the game begin]] and you're stuck to using your original weapon (the one you started with) and the Sword Of Plot Advancement again for the final battle.
** In ''VideoGame/PrinceOfPersiaWarriorWithin'' the Prince finds several of these: the Serpent sword which acts as a key granting him access to certain areas of the fortress, later the Scorpion sword, which can break through walls and will be used in something of a hail Mary plan, and finally the alternate-ending-providing [[InfinityPlusOneSword Water Sword]]
** The sword in level 8 of ''VideoGame/PrinceOfPersia2: The Shadow and the Flame'' has a cutscene of its own. It replaces the clumsy dagger you've been stuck with ever since you lost your old sword a few levels back.
* The lightsabers in some ''Franchise/StarWars'' games, usually coupled with Force powers. Acquiring/building a lightsaber typically marks the transition from a mere {{Mook}} to a full-fledged Jedi, in other words, [[TookALevelInBadass getting ten free levels in badass]]. This is when the ''real'' fun usually begins. Examples: ''[[VideoGame/DarkForcesSaga Jedi Knight II: Jedi Outcast]]'' and ''VideoGame/KnightsOfTheOldRepublic''.
* The eponymous Sigil in ''VideoGame/{{Strife}}: Quest for the Sigil''. It's the only weapon which can hurt bosses (well, a particular kind of boss). Not technically an EvolvingWeapon -- there is actually assembly involved. You just don't see it unless you're paying attention because pieces of the weapon automatically fly to you and self-attach when the enemy carrying them is defeated... even if you'd prefer they didn't.
* The Ultimate Legedary Epic Weapons in ''VideoGame/KingdomOfLoathing'' are upgraded from your Legendary Epic Weapons right before fighting the final, [[spoiler:demonic]] form of your Nemesis.
** This is made literal each time the Nemesis is confronted; the player is informed that the plot will not advance unless their Epic Weapon is equipped.
* The Armageddon Blade in ''VideoGame/{{Darksiders}}''. The last weapon you get -- however arguably not the most powerful.
* The Blade of Olympus in ''VideoGame/GodOfWar 2'' drains all your power from the first game and you spend the whole game searching for a way to retrieve it from Zeus' grasp. When you finally do, it's your main weapon in the boss fight with him.
* ''VideoGame/TacticsOgreTheKnightOfLodis'' has Longicolnis. Being a spear, it has some useful range advantages, can hit multiple enemies at once, gives bonuses to Virtue and Bane resistance, and unlike other spears doesn't have any movement penalties. However, there are a few weapons, aquired both before ''and'' after it, that are more powerful, though you still need it because you won't be able to harm the final boss without it.
** The original ''Videogame/TacticsOgre'' has Brynhildr. It's a powerful holy sword, and is necessary for the villains to open the way into the final area. It's quite heavy, though, which means that anyone equipping it will probably have fewer turns.
* ''[[VideoGame/{{STALKER}} STALKER: Call of Pripyat]]'' has the Gauss Rifle. Dropped by a Monolith [[BadassPreacher Preacher]], it's unusable for the first hour or so you're carrying the damn thing, but fixing it is incredibly important to the plot, and the damn thing can one-hit-kill just about anything you point it at.
* ''VideoGame/FarCry3BloodDragon'' has the Killstar. Once you start the mission to get it, you're locked into mission mode and can't go back to free-roam until the end of the story, but it's key to winning the game.
[[/folder]]

[[folder:Visual Novels]]
* The black sword acquired by [[spoiler:Mary Christie]] halfway through ''VisualNovel/ShikkokuNoSharnoth''. [[spoiler:It allows her to attempt reasoning with the Metacreatures, though that does not work. What it does let her do is cast it away to show that she intends to save Charlie and everyone else she cares about. Mind you, it would be a pretty potent weapon if she wanted it to be.]]
[[/folder]]

[[folder:Web Animation]]
* Tucker's Plasma Sword in ''Machinima/RedVsBlue'' starts out as a cool sword that can only be used by the "Chosen One", who is also the most evil (and/or stupid) individual in the universe (leading to a CrowningMomentOfFunny where [[OnlySaneMan Church]] names [[{{Cloudcuckoolander}} Caboose]] as TheAntichrist). When it's taken to the frozen northlands, it can be used to unlock and power up a CoolShip. It also gets a little philosophical when deciding wether it's really a key or a sword.
-->'''Church:''' So it ''is'' a sword. It just acts like a key in certain situations.\\
'''Caboose:''' ''Or'', it's a key all the time, and when you stick it in people, it unlocks their death.
[[/folder]]

[[folder:Web Comics]]
* The Sword of Xel Dum is a great example of this from the NSFW webcomic ''[[http://locus.departure-productions.com/archives/ Locus]]'' has a curse that requires the central character to kill whoever tries to take it for her, including the original owner... that's some plot advancement.
[[/folder]]

[[folder:Web Original]]
* In ''Literature/{{Phaeton}}'' Trayen gains the Omnisword near the end of series 1, the sword is the only way to finish of a defeated elementian permanently.
* In ''Roleplay/DeptHeavenApocrypha'', Monica's legendary sword Joyeuse is technically her CallToAdventure proper (and thus signals the First Act); learning to ''use'' it will be another matter, and once it's mastered her plot will move to its second act.
[[/folder]]

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