Barrier Maiden

""Lafrenze, don’t forget. You are the last guardian of the door that protects this world from the dead that dwell in Hades. You cannot ever break the barrier of purity.""

- "The Witch and Lafrenze", Elysion

Sometimes the Distressed Damsel isn't just a pretty and helpless love interest in need of rescuing; sometimes she's also a vital support beam for the continuing existence of a safe and happy world. Kinda makes dating awkward.

Much like a Virgin Powered Containment Field to a nasty Sealed Evil in A Can, the Fisher King (well, queen) of a kingdom, or a human Cosmic Keystone that makes sure the sun rises each morning, the heroes' Woobie is responsible for maintaining the Balance Between Good and Evil firmly in the Ghibli Hills side as opposed to Mordor.

Of course, this makes them the target of so many kidnapping plots even the parodies have become a Dead Horse Trope. Note that just plain killing the Barrier Maiden is rarely an option -- either the villain becomes infatuated with her or he wants to Break the Cutie to The Dark Side and turn her into an Apocalypse Maiden, or there's a complex Black Magic ritual needed before he can destroy or steal her power. Simply killing will just make her reincarnate elsewhere...the list goes on and on.

The life of a poor Barrier Maiden is pretty sucky to boot (even more so than for a superhero's kid). She's usually treated as a MacGuffin instead of a person, is expected to make a Heroic Sacrifice if victory is on the line, and is usually chained to a temple or altar as part of her duties. As a job, maintaining the Containment Field or being a Cosmic Keystone usually isn't pleasant either: if the evil is becoming stronger or the Eldritch Abomination is weakening reality, she might end up dying either holding up the roof or when the barrier breaks.

Expect the Barrier Maiden to be a White Magician Girl, The Messiah, Apocalypse Maiden or Pollyanna. Male examples are pretty uncommon, but Atlas at least is a good one, making this Older Than Feudalism. See also MacGuffin Girl and Holy Child. Not to be confused with the Barrier Warrior, but they may occasionally overlap. Also not to be confused with a Maiden Barrier, which can also make dating awkward.

Anime and Manga

 * from Gundam X, who's . A whole arc is about her
 * Also Maria Armonia from Victory Gundam, a powerful holy woman with Healing Hands and the puppet ruler of the Zanscare,
 * And later,
 * from Mobile Suit Gundam Age. How so?
 * The anime Blue Seed has Momiji, a girl from a family line whose daughters, descended from the aforementioned Princess Kushinada, must ritually sacrifice themselves to seal the dreaded Orochi from rising again. Things were fine until twin girls (the aforementioned Momiji Fujimiya and her older twin Kaede Kunikida) were born, "splitting" the bloodline and rousing the demon. Of course, it doesn't help that
 * Ulrike and Ondine from Kyo Kara Maoh; being stuck in the same building for 800 years without cable would be torture.
 * In Magic Knight Rayearth this is part of the job description of the Pillar of Cephiro, and is the factor that drives the Backstory and underlying plot.
 * in Mahou Sensei Negima, mixing it with Action Girl.
 * Modern-day high-tech example: Chise from Saikano is the ultimate weapon on whose shoulders the fate of Japan depends...and the invasion is underway. When she tries to take time out for dating, lots of people die.
 * Saori Kido aka Athena from Saint Seiya frequently stood in this position. Notably in the Asgard (anime only) and Poseidon arcs, she uses her goddess' powers to delay Princess Hilda and Poseidon from flooding the planet and killing humanity. The effort was usually such a strain on her that it was a race against the clock for the saints to battle their enemies before time ran out and Saori died.
 * Also, Shun's Training From Hell and armor are heavily based on the legend of Princess Andromeda from the myths. You can guess what role he's filled more than once during battle...lampshaded very often when his backstory is explained and everyone wonders if Shun's destiny is to die for others like Andromeda was willing to do.
 * In Soul Eater the Shinigami sealed himself to the ground of what became Death City in order to imprison the first Kishin, Asura. 800 years later, Asura gets out thanks to Medusa's Magnificent Bitch credentials, but for the sake of the manga's storyline Shinigami stays put. The anime, however, finds a way around that.
 * In Star Driver this is a main focal point for the plot. The reason that the Humongous Mecha don't show up in the middle of the island is because there are four maidens that contain seals to keep them in Zero Time; the bad guys want to break the seals so they can use the devastating weapons in reality. The show starts right after the villains have broken the first seal. THE BM here is Wako, one of the Maidens: not only she's a valuable MacGuffin Girl, but anytime a fight starts she gets trapped in a force-field bubble. That's not being snarky; that is literally how it works.
 * Reversed in Slayers Next. Lina Inverse is the only person who can destroy the world...but she's actually a Black Magician Girl.
 * Kotori Monou from X 1999, who unbeknownst to her is one of the keys to the world's doom or salvation.
 * Kurogane's mother from Tsubasa Reservoir Chronicle was one of these. She was the miko to the local shrine which maintained the barriers keeping the demons at bay, and
 * from Naruto.  She's also the rare Barrier Maiden who mixes this is Action Girl, since she was in a Battle Couple with
 * A sort-of unofficial example is . Aaaaaaargh!.
 * Both chosen children Naruto and Nagato could be considered male examples of this.
 * The jewels inside the magical girls of Rakugo Tennyo Oyui are also what enforce the barrier around Edo. As far as barrier maidens go, though, they're pretty active in the field.
 * in the manga version of Karin.  Therefore,
 * A certain character in Haruhi Suzumiya is a barrier for herself; if she gets in a bad mood, or discovers her own volatile abilities, she's likely to unintentionally erase the entire Universe (while not even being aware that she'll do so). No one is sure what would happen if she died, but she seems to have, so it probably wouldn't be good.
 * In The Place Promised in Our Early Days, ends up in a coma, which somehow prevents  from overwriting the world with part of a parallel universe.

Comic Books

 * An issue of the Buffy the Vampire Slayer, Season Eight comic features a young woman performing this task for a demonic house and not feeling at all well thereby. The character was based on a mentally ill fan, who evidently liked it.
 * Fantastic Five, a what-if future continuity of the Fantastic Four, sets Sue Richards up as one in a quite literal sense. It's used as a surprise twist:

Film

 * The protagonist of The Sentinel (not the television show).
 * Leeloo from The Fifth Element is another example of this.
 * The titular character from The Golden Child is a rare male example.

Literature

 * The Childlike Empress in The Neverending Story was a Fisher King for the land and her illness is thought to be what's causing The Nothing that's destroying Fantasia, but her sickness is actually due to her needing a new name. (Fantasia is failing because . The two problems are related and can be solved in a similar manner.)
 * Ehlana, Queen of Elenia in the Elenium trilogy by David Eddings, serves as a Barrier Maiden during the first 2 1/4 books. The ghost of a dead knight comments to the series protagonist that "the darkness hovers at the gate, and Ehlana is our only hope of light." The action of the series mostly focuses around recovering the mystic artifact that will keep the poisoned queen from dying, and thus prevent the world from succumbing to the grip of evil.
 * Unusual in that it's not any magical power she has that makes saving her critical, but that allowing the next in line (her cousin and suspected half-brother) to take the throne would give the villains enough cash to buy leadership of the church and turn it into a Church of Evil.
 * In The Elfstones of Shannara, one of the main characters is a Barrier Maiden.
 * While the Archive from The Dresden Files doesn't actually prevent the destruction of the world by her existence, she is a repository of all mankind's knowledge and knows everything that is ever written down. Particularly in Small Favor, she's treated as quite possibly the single most badass Barrier Maiden in all of history.
 * Jade Pearl, of Bridge of Birds, is a rather atypical Barrier Maiden.
 * A rather darker example of the trope: in The Vampire Chronicles, the first vampire, Akasha, is in suspended animation and closely guarded in an underground vault by her vampire servants, since, while she herself is virtually indestructible, if she is harmed, all the vampires dependent on her would be destroyed. In ancient times, a usurper places her in the sunlight: while she only receives a tan, vampires around the globe burst into flame.
 * There is a clear example in Tolkien's The Silmarillion: Melian the Maia uses her powers to guard and defend Doriath with a protection called the Girdle of Melian.
 * Galadriel does the same with Lothlorien in The Lord of the Rings. It should be noted that it was Melian who taught Galadriel her stuff.
 * Senna from Everworld serves as some sort of weird cross between this and Apocalypse Maiden. She's basically a living portal between Everworld and "the Old World" (ours), and several forces in Everworld want her for various reasons. An added twist: in a world full of murderous deities and a god-eating Eldritch Abomination, she intends to become the Big Bad herself.
 * It helps that she's raised an army of cultists around herself in the Old World, and intends to bring them to Everworld, where she will use their 20th century tech to overcome the gods.
 * The Eternals from Fablehaven are a group of immortal Barrier People (not all maidens) who serve as . Immortality has not been kind to them, such that it is not actually all that difficult for them to be convinced to take their own lives.
 * Princess Jenna from Septimus Heap. Basically, the safety of the Castle depends upon her presence in the Castle, leading to both the plots of Magyk and Flyte as she is persecuted by DomDaniel and actually kidnapped respectively.

Live Action TV

 * Dawn of Buffy the Vampire Slayer is . Season Five centers around a Sealed Evil in A Can trying to leave Earth by using Dawn. Not only that, but near the end the heroes get into a discussion of what to do if the worst happens, and we get to watch
 * Lunagel (Rin) from Mahou Sentai Magiranger is the gatekeeper whose body and life keeps the evil monsters imprisoned in Infershia. Clare serves as her US counterpart in Power Rangers Mystic Force, though unlike previous gatekeepers, she nonsensically gets to stay alive when the gate is inevitably broken.
 * A bit different in both versions. In Magiranger, her life force maintains the seal, so if she is killed, the gate will open. (The wheel thing above her head while she was captive, there in both versions, was to break the protection spell that normally makes this impossible.) In Mystic Force, the title of Gatekeeper is passed down, but fully sealing the gate killed Clare's mother, so it's said that opening it will kill Clare. The wheel thing was designed to tap that power. (She should still have died, though, and there wasn't even a Hand Wave. Rin, on the other hand, is in the clear, as it's not operating the gate that would kill her, but the other way around.)
 * in the Doctor Who serial "The Armageddon Factor."
 * The Keeper of Traken from the serial of the same name is quite possibly the inspiration for the Magic Knight Rayearth example. The Keeper has great pwoer, but having to focus that power to maintain the Traken Union has to get And I Must Scream-y after having to do it and nothing else for years and years and years, but that's not the plot point that it is in Rayearth. Also, like Rayearth, there are still those who want to take the position despite knowing this.
 * In Supernatural we get who is the final seal holding Lucifer in his cell. Once she's dead, he's free to bring the apocalypse. Interestingly, there's a completely separate (male) character serving as the Apocalypse Maiden.
 * The Imagin of Kamen Rider Den-O want to make their Alternate Timeline a reality by destroying the existing timeline. They travel to the past, laying destruction there, but the existence of Singularity Points (the Kamen Riders) prevent any permanent changes. The Big Bad then figures out that a special Singularity Point, called the "Junction Point", is the one keeping the timeline stable, and that the Imagins' victory will only be ensured by destroying the Junction Point.

Mythology

 * For crimes against the Olympians, Atlas, one of the Titans from Greek myth, had to carry the heavens (not the Earth itself, but the sky above it) for all eternity. He was ultimately turned to stone by Perseus for being a Jerkass to him on his way back; whether or not he was still aware is up for debate. But then Perseus was one of Hercules's ancestors.
 * An example from the Christian martyrology: the unnamed Princess from Saint George of Cappadocia's legend, as well as her Japanese counterpart, Princess Kushinada from the Orochi myths.

Tabletop Games
"Once, there was a maiden...
 * Ashling from Lorwyn was supposed to be one of these,
 * Exalted:

....and before her came all the peoples of Creation, and knelt.

They set aside their petty squabbles in her name.

They acclaimed her with many shouts.

They prayed for her safety, and her weal.

Not one of them struck free her chains.

"To know the world..."

"...is to own it," she said."

Video Games

 * In Kingdom Hearts The Seven Princesses of Heart collectively have the power to reveal the keyhole necessary to get to Kingdom Hearts, the origin of life in the universe and a recurring MacGuffin. The bad guys do all they can to find the missing Princesses so they can fully take over.
 * On a bigger scale, the Princesses' hearts of pure light repel darkness and keep all the worlds in the Realm of Light safe just by being there.
 * Aerith Gainsborough from Final Fantasy VII is the only person who can summon Holy and save the world.
 * Bastila Shan in Knights of the Old Republic, though this is due to her incredible skill with battle meditation and her, so she is much more of an Action Girl than most Barrier Maidens.
 * In the Seiken Densetsu, aka Mana, game series,  is not the same Mana Goddess that created the world as legend says, but is  . This is played to particularly devastating effect in Sword of Mana, the remake of the first game, in which  . It's particularly devastating in   route since.
 * In the Touhou games, the main character Reimu Hakurei maintains the barrier between Gensokyou (a sealed-off Fantasy Kitchen Sink) and the rest of the world. She's also very lazy, but she has a lot of innate power. "If [danmaku combat] wasn't just for play, no one could defeat her with any method." In fact, the Spell Card rules that turns combat into something more like a game for spectators to watch was created more for the sake of the youkai than for Reimu, since it allows them to win without killing Reimu and subsequently dooming the Magical Land they live in.
 * The Legend of Zelda a Link To T He Past has seven of these (successors to the seven Sages in Ocarina of Time) maintaining the seal on the Dark World. Princess Zelda also takes on this role voluntarily in The Legend of Zelda Twilight Princess, first when she, and again later when she
 * The Legend of Zelda Skyward Sword does it again with
 * Likewise, Dragon Quest VIII featured seven descendants of the ancient seven sages who sealed Rhapthorne in the Godbird Sceptre, and who Rhapthorne had to kill (using others as pawns) to restore his corporeal form. The fate of these descendants is obvious.
 * In Skyrim the Thalmor have made worshipping Talos illegal. Why?
 * Princess Peach in the original Super Mario Bros
 * The Barrier Maiden thing was abandoned for a while, with Bowser's Motives changing from pure conquest to trying to win Peach's affection. However, more recent games have restored her Barrier Maiden status, though in a different form each time.
 * In Yoshi's Island DS, Baby Peach is one of the Seven Star Children who are born with great power. Bowser attempts to steal the children to take over the universe (this would include Kidnapping himself, which would result in a few time related issues...) Peach is actually one of the children who escapes capture, and assists Yoshi and Baby Mario in saving the others.
 * In Mario and Luigi Superstar Saga, Peach's voice is the only thing that can awaken the Beanstar, which grants wishes.
 * In Super Paper Mario, Peach and Bowser are a Barrier Couple. If they ever got married, the Chaos Heart would be formed and begin to destroy the world. Naturally, this is the first thing the Big Bad does in the first part of the game. Peach is so easily kidnapped...
 * Fatal Frame. It's eventually revealed that Barrier Maidens were used to ritually seal the Hell Mouth under the house.
 * Fatal Frame 2: The BarrierMaidens are twin girls (or twin boys). One of them is sacrificed to hell...darkness...abyss thing to prevent it from devouring the village, while the other stay in the village to act as a living goddess of some sort. The real Squick part? The girl who is to remain alive must strangle her sister as an act of sacrifice. And that's just the beginning of the circle of tragedy that engulf a lot of people, including the protagonist Mio and her handicapped twin sister Mayu.
 * Colette from Tales of Symphonia, the Chosen One, intended to sacrifice herself to keep the evil of the Desians sealed away. Really suffers for it, both for the cost of performing her mission, as well as most of the villains and even a few others treating her as a MacGuffin..
 * Richea Spodune of Tales of Hearts is the non-sacrificial version, and a double serving. First, she's the only thing holding The Heartless in check. When she's temporarily incapacitated, the Zerom and their symptomatic Despir Sickness return to the world like a sledgehammer. Second, the Big Bad requires her power to activate the Space Whale to go release a world-eating monster (he has a reason, trust me). . Yet another variant example is a massive Power Crystal powering a barrier protecting the village of Norquin. The maiden here is dead, but it's said that her will to protect the village remains in the Psistone and powers the barrier.
 * Furiae in Drakengard.
 * of Persona 3 is one of these, holding back.
 * The PSP portable version adds
 * Another spin of the Kushinada myth is used in King of Fighters 97 with Yuki, Kyo Kusanagi's Tsundere girlfriend.
 * Another character from the same series, Kyo and Yuki's friend Athena Asamiya, is a rare case where the Barrier Maiden is also an Action Girl. As an Expy of the already mentioned Saori Kido, this is expected.
 * Also in this category, in World of Warcraft, is
 * Summoners in Final Fantasy X would qualify
 * A villainous version also appears in Final Fantasy X in Yunalesca.
 * Shana, from Legend of Dragoon, is an evil example. At first, you think of her just as The Chick and The Medic, but then you discover she is the Moon Child, the only being able of resurrecting the Virage Embryo, last boss of the game. Until she is used by Melbu Frahma for this purpose, no one, not even her, is aware of her real identity.
 * Misha, one of the three potential love interests in Ar Tonelico. 
 * Rare male example: Martin Septim in The Elder Scrolls: Oblivion, like the other Emperors before him, is the only person who can carry out the ritual that seals the barrier against Oblivion.
 * Sakuya from Okami is a cherry tree spirit and powerful protector. Her guardian saplings protect the nearby lands from evil, and their corruption not only weakened her into a coma but allowed evil to flourish. Amaterasu's missions largely revolve around restoring her saplings, culminating in Sakuya being restored and "refreshed" as the page picture shows.
 * Kukuru from Arc the Lad I & II.
 * Dragon Quest VII has a particularly cruel version, with, as she's being used by the monsters as a Barrier Maiden sealing away  . Making matters worse is that she's a Broken Bird due to her past:.
 * In the Girls Love Visual Novel Akai Ito, this is the job of whoever is taking the role of Ohashira. The first Ohashira was Otsune, and in the present day it's Yumei. The Ohashira essentially become a ghost to seal the soul of Nushi with all the might of her soul. It's quite similar to the myth of Sakuya mentioned above. In fact, a character named Sakuya was really attached to Otsune.
 * Nostalgia has one in Fiona.
 * It was in Mega Man Zero 2 did we finally find out what happened to the hero of the previous series. And it just so happens to be the goal of the Big Bad of Zero 2.
 * In Dark Souls, Gwyn, Lord of Sunlight, is this by virtue of being the Lord of Sunlight.  Whether or not that is a good thing is an entirely different matter.
 * Hazuki Kazama from Samurai Shodown, a girl who used her powerful sealing techniques to tame and seal two inmensely strong spirits, Enja and Suija, in the swords of her two older brothers, Kazuki and Sougetsu. Too bad that Amakusa heard about Hazuki's abilities and took a hold of her for the worst...
 * A gaint dragon, in Breath of Fire 2 is seen blocking the door that leads to the final dungeon to keep the Big Bad from coming out.
 * A gaint dragon, in Breath of Fire 2 is seen blocking the door that leads to the final dungeon to keep the Big Bad from coming out.

Webcomics

 * Snowman from Homestuck is an evil Barrier Maiden--no one will kill her because they know if they do the whole universe will end, and she takes advantage of this to torment Spades Slick without fear of retribution.

Western Animation

 * Varla from Dungeons and Dragons is both this and a Reality Warper. Poor, poor little girl
 * and the other Guardians from WITCH may be partial examples, as the Veil that separates the worlds is drawn from the Heart of Candracar and the resulting drain on their power makes them weaker during Season 1,  having the worst of it since it deprives her of any offensive ability; she doesn't even know what her elemental affiliation is! When the Veil is lowered in Season 2 all the Guardians receive a power boost as their powers return,.
 * In South Park Bigger Longer and Uncut,  are the only two people preventing the apocalypse from being brought about.
 * The Multiverse in Turtles Forever is tied to the existence of ; if they die, then say bye-bye to the multiverse.