History Main / Geas

* In ''FanFic/LongRoadToFriendship'', the Elements of Harmony place Sunset Shimmer under a geas as a result of her previous behavior as an AlphaBitch. The curse makes it so Sunset always has to tell the truth when she's asked a question, and makes it so she has to do what anyone politely asks her to do, especially if they say "please". A later chapter reveals that the latter overrides the former, as Twilight asks Sunset to "please lie", and Sunset starts compulsively lying.

However, having a geas placed upon you isn't all that bad - [[OathboundPower as long as you conform to it, it can actually make you stronger]]. They can also be used for a GameOfChicken, where someone goes under geas in order to goad a rival into accepting an equal or greater geas.

* A very interesting case in ''Manga/{{Bleach}}'' is Giriko and his Time Tells No Lies ability. Essentially, it's a contract he invokes on himself or on others, with the spirit of his watch. It can take multiple forms; increased strength, the power to kill by line of sight, and so on. The catch is that no party involved can violate this contract, or they'll be incinerated--the part that makes it a Geas. Wonder what ever happened to [[spoiler:Giriko's eye?]] Sadly, Giriko doesn't see much action.

* As befits the genre, the 3rd Edition ''TabletopGame/{{GURPS}}'' sourcebook Celtic Myth has rules for imposing geasa on characters.
* There is a spell called geas in ''TabletopGame/DungeonsAndDragons'' that forces the character to fulfill the terms. Refusing to do so (even unintentionally) can carry some nasty consequences. Clerics call the same spell "Quest", and also have a "Mark of Justice" that places a curse on a character who breaks the conditions of the Mark.
** The powers of Wu Jen and characters under the various Vows of the Book of Exalted Deeds have specific behaviors or tasks they must perform to maintain their powers.
* Geasa were used in 3rd edition ''TabletopGame/{{Shadowrun}}'' to recover points of magic that had been lost by shaman/magicians/adepts. Your character had to accept some sort of condition to recover a point of magic. Usually anything the GM wanted/was willing to allow but classic ones were some sort of talisman that you had to keep on your person, having to fast on a regular basis, spend time in meditation, or only use magic in certain circumstances. Breaking the geas reduced your magic back to it's normal level.
* In ''TabletopGame/MageTheAwakening'', geasa can be inflicted by mages who have gained Mastery of the Fate Arcanum. Working against the terms of a geas (or even failing to actively do something required by the geas) inflicts a very debilitating curse. A geas (and the curse for breaking it) can be made hereditary, affecting the subject's descendants as well.

* This is the power the demonic lilim have in ''TabletopGame/InNomine''. They can look into a person's eyes and discover their true desires (ranging in intensity from 'needs a light for their cigarette' to 'needs to get a million dollars'). If they then fulfill one of them (or more) for the person, they can (attempt to) attach a geas to the person to do something in return. They're limited only by the scale of the desire (an easy-to-fulfill desire would grant a geas that only lasts an hour or so) and the target's ability to resist the compulsion. The dangerous part is the target is usually ''not aware'' the lilim is doing this, and doesn't have to agree to a DealWithTheDevil for the lilim to get the geas. The only real defense is a combination of never looking a lilim in the eyes, and never accepting anything they offer, ever.
* In ''TabletopGame/{{Exalted}}'', [[AbusivePrecursors the Primordials]] placed one on their creations, [[ServantRace the gods]]. It forbade them from directly attacking any Primordial (except in self defence or on the order of [[KingOfAllCosmos Theion]]). The gods got around this by giving power to mortals whose free will means that their actions are seen as sperate from the gods. They were then free to help these humans as long as they themselves didn't attack a Primordial; anything else was fair game.
* In ''TabletopGame/KitsuneOfFoxesAndFools'' "geased" is a consequence that prevents a fox from regaining foxfire for two turns.

* The immortals from ''WesternAnimation/HighlanderTheAnimatedSeries'' are under one of these, having all taken a mystical oath to never be able to kill another immortal. Of course, [[BigBad Kortan]] waited until all the others had taken the oath and then didn't, effectively rendering him invincible to everyone who could ever stand against him. [[WhatAnIdiot Didn't really think that one through, did you guys?]] A couple of the immortals, known as Jettetors now, have figured out ways to [[LoopholeAbuse weasel out of the geas]]: Cornell changed his name to "Orion" since the oath mentioned them by name specifically, Matsuda built a cyborg to fight on his behalf, and of course the main character Quentin was born after the fact and thus never took the oath in the first place.

** Zeldris wields the Commandment of Piety; any who shows "disloyalty" (this could mean something as simple as turning around to run away from him) will be brainwashed to sevre the Demon King. Since the Ten Commandments are loyal to the Demon King and Zeldris is his personally appointed executioner, this basically means that he is calling the shots.

* In ''Fanfic/TheSaviorKingTheMasterTacticianAndTheQueenOfLiberation'', [[spoiler:the [[VoodooZombie resurrected Ten Elites]]—specifically Blaiddyd, Fraldarius, Riegan, and Lamine—]]are kept under one by the Agarthans that forces them to be their living weapons. It's not as powerful as the Agarthans would like, however, as [[spoiler:each of the Elites]] in one way or another tend to [[FromACertainPointOfView creatively interpret]] their commands and even outright threaten their masters.

Compare: TheFettered and ObstructiveCodeOfConduct (for mundane versions of this), MagicallyBindingContract (which can have similar effects but is more of a deal rather than a spell or curse), NoManOfWomanBorn (for when this is a prophecy rather than an oath) and RestrainingBolt (where an object produces similar effects).

* ''Series/TheWheelOfTime'': Aes Sedai are bound by magic to keep three oaths stopping them from lying or harming others (absent some extreme circumstances) with their powers. It was done in hopes this would make them more trusted by people, but that hasn't worked out very well (given they find a lot of [[LoopholeAbuse loopholes]] with the oaths, to start).

** These are called "Unbreakable Vows" in ''Literature/HarryPotterAndTheHalfBloodPrince'', wherein [[TheMole Severus]] [[TheMole Snape]] agrees to let Narcissa Malfoy place this spell on him as an act of good faith. It's explained that breaking the vow is fatal, but this never actually happens in the story so details are vague.

** Figures prominently into the second book, ''The Jennifer Morgue'' where the protagonist is put under a reality-warping geas that essentially transforms him into a [[Film/JamesBond James Bond-esque]] hero (Turns out [[spoiler:this is exactly what the BigBad wants, as he plans on dismissing the geas right before the protagonist is about to win, at which point RealityEnsues and he can kill the protagonist easily. Fortunately, it turns out the protagonist was actually playing the role of ''Bond girl'']]).

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* Pearl of ''WesternAnimation/StevenUniverse'', in several episodes, can be observed slapping her hands over her own mouth when certain subjects come up in conversation. It's revealed late in Season 5 that this is under command of her original owner, [[spoiler:Pink Diamond, to never again speak of how the two of them faked Pink Diamond's shattering at the hands of "Rose Quartz", who for that instance was Pearl in disguise, but otherwise was actually ''Pink Diamond herself.'' Luckily this is a slight variant, as Pearl couldn't outright admit the truth, but once Steven (Pink's son) found out about it, Pearl's "spell" is broken as she can freely and happily give the backstory on ''why'' this happened]].

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* In ''[[Creator/SimonRGreen Blood And Honor]]'', Brion [=DeGrange=] was a bandit leader until he was captured and [[BoxedCrook condemned to servitude]] at Castle Midnight. He was placed under a geas that compels him to work as the castle's head of security, and bars him from any act - drinking to excess, venturing outside, seeking female companionship - that might distract from or diminish his performance at that task. But it doesn't bar him from ''absolutely hating'' every minute of it.

* In the ''Literature/InheritanceCycle'', a character who swears an oath in the Ancient Language is incapable of breaking it (though they only have to obey the letter, [[LoopholeAbuse not the spirit]]). What is more, a person can be compelled to swear such an oath by someone who knows their true name. There is an out, however-if who they are changes so much that their True Name in the Ancient Language changes, all oaths they've sworn up to that point are null-and-void.

** Grayroad wields the Commandment of Pacifism (also known as "Thou Shalt not Kill" depending on the dub); anyone who kills in their presence will have their presence will have their time stolen from them, causing them to age to death within moments. The only way anyone can width-stand the Commandment is either not kill anyone (which is hard when you're Grayroad's enemy) or if you possess [[ImmortalityBeginsAtTwenty eternal youth]] like Merlin and Ban.

** These are called "Unbreakable Vows" in ''Literature/HarryPotterAndTheHalfBloodPrince'', wherein [[TheMole Severus]] [[ReverseMole Snape]] agrees to let Narcissa Malfoy place this spell on him as an act of good faith. It's explained that breaking the vow is fatal, but this never actually happens in the story so details are vague.