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A Treacherous Advisor character is the type the {{heroes}} consult when they're digging up an AncientConspiracy, or something of the sort, and have hit a dead end. Surely he's in a position to be helpful? After all, he's the scholar/politician/military man/whatever, and just likely to have the information they need. Not to mention he can keep a secret.

Unfortunately, this trusted expert is secretly one of the bad guys. Sometimes he may even be the BigBad himself! What makes him different from your average [[TheMole Mole]] is the degree to which the heroes require his assistance -- he's not a regular part of TheTeam, but he's the only person who can give exactly the help needed.

The dead giveaway for this character type is accepting the heroes theories with a complete lack of skepticism. If it were anyone else, the first thing out of their mouth would be, "Why should I believe you?" If the character says "[[HaveYouToldAnyoneElse Have you told anyone else]]?" or "It's a good thing you came to me." be warned: they're either about to give TheReveal or planning on making some calls and starting a massive cover-up as soon as the hero leaves the room.

Another common trait of Treacherous Advisors is storing the {{Plot Coupon}}s [[MacGuffinDeliveryService the heroes are fetching]], revealing themselves once they have the last one. In these cases, a common giveaway is their seeming a little too interested in the {{Plot Coupon}}s, more specifically in the act of taking them. A dead giveaway is if he doesn't let the hero look at the ones he's already collected. The hero will sometimes catch on as he's returning the last one, but never before then.

In a TournamentArc, the Treacherous Advisor may be the one who helps the hero reach the finals because he (or his BigBad boss) has a trap waiting in the final round.

They appear to be benevolent {{Mentors}} or ReasonableAuthorityFigure, until their TheReveal shows their true nature. On rare occasions, such as in a ConspiracyThriller, ''everyone'' of importance whose help the hero seeks is a mole; the hero's only real allies are the ones with no power or influence.

Not to be confused with the EvilChancellor. Contrast SarcasticDevotee and DeceptiveDisciple. Compare BigBadFriend and RegentForLife. Despite its name, the EvilMentor and this trope rarely overlap as the Evil Mentor will not try to hide its true nature.

'''WARNING: Examples can be major spoilers for a climactic [[TheReveal reveal]]. Read ahead at your own risk.'''



[[folder:Anime and Manga]]
* Gil Graham in ''Anime/MagicalGirlLyricalNanohaAs''.
* ''Anime/YuGiOhGX''
** Subverted in : Daitokouji-sensei, Judai's teacher and ally, was revealed to be TheMole, and then later TheMole for the good guys.
** Played straight [[spoiler:with Edo Phoenix's adoptive father DD. He was a criminal who murdered Edo's true father and stole the Ultimate D card, becoming a vassal of the Light of Ruin in the process; the whole reason he took Edo under his wing was to throw suspicion off of himself. Eventually, he confronted Edo and the truth came out, but Edo defeated him (ironically, using a card that his father designed to defeat the Ulitimate D card) and DD perished in the resulting fire.]]
* [[spoiler:Kabuto]] in ''Manga/{{Naruto}}'''s Chuunin Exam TournamentArc.
* [[spoiler: Colonel Urube Ishikawa]] in ''Anime/MobileFighterGGundam''.
* [[spoiler: Kirei Kotomine]] in ''VisualNovel/FateStayNight'', though neither Rin nor Shirou trust him very much anyway.
* ''Words Worth'': Both Tessio of the Shadow Tribe and Menza of the Light Tribe, who are later revealed to be [[spoiler: two halves of the same entity, who is pushing the tribes to remain in a constant state of war to keep the Words Worth Tablet prophecy from being fulfilled.]]
* BigBad [[spoiler: Albert Maverick]] from ''Anime/TigerAndBunny'' is this to [[spoiler: Barnaby. He steers Barnaby to become a highly marketable (and easily-manipulated) corporate-sponsored {{superhero}} who works tirelessly for the company and TV channel of which he is the CEO. Barnaby constantly looks to Maverick for guidance (and obviously considers him to be a ParentalSubstitute) for more than two-thirds of the series.]]

[[folder: Comic Books]]
* [[spoiler:Haazen]] in ''KnightsOfTheOldRepublic''. He manipulates [[KnightTemplar Lucien Draay]] into doing some truly nasty things -- including ordering the deaths of several of his colleagues apprentices and trying to kill his own -- because that was supposed to prevent the return of the Sith. [[spoiler: Turns out Haazen was Sith himself, and was aiming to both control the Jedi through Lucien and generally spit on the grave of Barrison Draay, Lucien's father and Haazen's one-time friend-turned-rival]].
* In ''Comicbook/{{Bookhunter}}'', after the Library Police finally retrieve the stolen book, Agent Bay realizes that the stolen copy was actually another forgery--because the original book had already been stolen by the Chief of Library Security.
* ''SpiderMan''
** When NYPD criminologist Carlie Cooper discovers Officer Vin Gonzales is part of a conspiracy to frame Spidey, she goes straight to the precinct sergeant. He turns out to be deeper in it than Vin, and quite prepared to pin the whole thing on Vin and Carlie.
** ComicBook/UltimateSpiderMan had Jean De Wolffe. Her regular 616 Marvel universe counterpart was a by the book cop who had a soft spot for Spider-Man, and whose death was a tragedy. Her UltimateUniverse counterpart seemed to be shaping up to be similar, sending Spider-Man to potential bad guys' hideouts but in the end turned out to be working for the [[BigBad Kingpin]] and unceremoniously shot by ThePunisher because he knew she was a bent cop.
** Then there was Ezekiel. This mysterious man whose powers seemed to be the same as Spidey's (except mystical in nature, not scientific) helped him against Morlun and Shathra, predators of supernatural origin bent on preying on the hero. Ezekiel told Spidey that the spider that had bitten him was not mutated by the radiation, but actually ''trying'' to give him its powers before the radiation killed it. This meant that Spider-Man was now part of the supernatural food chain, and had become a target for other totems and beings who feed on totems (Hence why so many of Spider-Man's foes were based on animals; on some level, they 'sensed' that Peter was a true totem while they were merely impostors and were thus driven to destroy him. [[spoiler:But it was all lies. It was later revealed that Morlun and Shathra were really after Ezekiel, and Ezekiel attempted to direct the consequences of gaining his powers onto Spider-Man himself, taking Spider-Man to the temple where he had been given his own powers and drawing blood to attract a massive spider that would take the 'false' totem warrior as a sacrifice. At the last moment, however, [[MyGodWhatHaveIDone he realized that he had done nothing but selfish things with his powers]], while Peter had selflessly risked his life to save others again and again. With that in mind, he attacked the spider, [[RedemptionEqualsDeath sacrificing himself to save Peter]].]]
* In ''ComicBook/AllFallDown'', [[spoiler:AIQ Squared]] is this to Siphon and the Pantheon. Mildly subverted in that he is legitimately looking out for IQ Squared's best interests.
* The French series ''ComicBook/LaQueteDeLOiseauDuTemps'': [[spoiler:Mara, the old witch-princess who sends the heroes on the quest in the first place]], secretly wishes to steal the powers of the GodOfEvil as opposed to [[SealedEvilInACan sealing him]].

[[folder: Fan Fic]]
* ''FanFic/MegaManDefenderOfTheHumanRace'' has Governor Deacon's adviser, Newkirk, who didn't have well-laid plans. While not outright treacherous, he showed little to no concern for public safety. This got Newkirk fired.
* ''Fanfic/TealovesSteamyAdventure''. The story starts when a conversation with Pinkie Pie convinces Tealove to go on a quest to obtain some magic tea leaves. Pinkie even offers some advice for the trip. By the end of the story, Tealove has the magic tea leaves, and she has to keep them out of the hooves of an evil cultist. The cultist is very, ''very'' strongly implied to be Pinkie Pie in a disguise. Amusingly, [[SerendipityWritesThePlot this twist came about completely by accident]]. The story was a RoundRobin with no communication between the different authors--so the guy who wrote Pinkie as the cultist had no idea that she'd appeared earlier as the quest-giver.
* In the ''Fanfic/BlackCrayons'' series, one of the installments ''A Child's Innocence'' has [[spoiler: Sentinel Prime, Optimus Prime's mentor, revealed to be EvilAllAlong.]]
* ''Fanfic/HarryPotterAndTheMethodsOfRationality'' has [[spoiler: Quirrell/Voldemort who was one of the few adults Harry felt he could almost trust]]

[[folder:Films -- Animated]]
* [[spoiler:Odin]] in ''WesternAnimation/HeavyMetal2000'' reveals himself to be one of the aliens responsible for creating the fountain of youth and to have been seeking its power all along after the death of the primary villain Tyler.
* Captain Korso in ''WesternAnimation/TitanAE'' is a rare example who goes to the trouble of searching out the not-yet-hero, convincing him to join their quest if only for a nicer place to live, inspiring him to believe in a cause other than his own self-interest or personal profit... and then revealing himself to have been working for the bad guys all along just for a big check.
* When Mike and Sully first uncover Randall's plot in ''WesternAnimation/MonstersInc'', Sully tries going to their boss Mr. Waternoose for help. Five minutes later, he's asked them [[HaveYouToldAnyoneElse if anyone else knows about it]] and has banished them to the human world.
-->'''Mike:''' Oh, what a great idea going to your old pal Waternoose! Too bad ''he was in on the whole thing!''

[[folder:Films -- Live-Action]]
* The main antagonist in ''Film/PrinceOfPersiaTheSandsOfTime''.
* In ''Film/Another48Hours'', a RetCon makes Jack Cate's fellow officer and longtime friend Ben the BigBad whom Reggie Hammond had robbed in the BackStory to the first film, and the one who has been feeding Jack misinformation all along.
* ''Film/IndianaJonesAndTheLastCrusade.'' Both [[spoiler: Walter Donovan and Dr. Elsa Schneider]] would qualify.
* [[spoiler:Obadiah Stane]] from ''Film/IronMan1''. Not a big secret to those who know his history from the comics, but in the film, [[spoiler:he founded Stark Industries with Tony's dad and pretends to be Stark's friend and mentor, but when the film begins, he pays to have Tony killed while on a trip showing off some of his new weapons (they don't, because they weren't told who he was). Later, he ends up building his own armor suit. Which he powers with the power source he pulls out of Tony's chest. Which was all that was keeping him alive.]]
* [[spoiler:Lt. Neil Briggs (Hal Holbrook)]] in ''Film/MagnumForce''. His dismissal of Harry's CowboyCop methods is just him blowing smoke. He's a far more extreme VigilanteMan KillerCop than Harry himself.
* Elijah Price in ''Film/{{Unbreakable}}''. Everything Elijah teaches David is so that he can be a great superhero and save people from other villains, but he has ulterior motives for guiding David on his journey. He wants David to be the hero so he has an enemy to fight and justify his role.
* The B-movies ''Full Contact'' (1992), ''Dragon Fire'' (1993) and ''Bloodfist 2050'' (2005) all use ''exactly'' the same plot: a kickboxer who participates in the underground pit-fighting circuit in order to find the guy who has killed his brother. In each one, it turns out that the killer is the very guy who trained him.
* ''Film/{{Watchmen}}'' adds shades of this to the relationship between [[spoiler:Dan and Adrian, due to the fact that unlike in the graphic novel, they're close, affectionate friends in this version]].
* [[spoiler:Teddy Gammel]] in ''Film/{{Memento}}''. Complicated because his intentions aren't purely evil. While he's manipulating Lenny for his own purposes, [[spoiler:he also does it to help Lenny function in daily life, and Lenny is also manipulating ''himself'' into killing innocent people just so he has a purpose in life. Teddy is a smug and greedy enabler, while Lenny is a willing SerialKiller... and tragically doesn't even remember it.]]
* Los Angeles Narcotics Detective Alonzo Harris from ''Film/TrainingDay'' is THE poster boy of this trope.
* Palpatine is like a father to Anakin in the Franchise/StarWars prequel trilogy -- he's also Darth kriffing Sidious.
* Lieutenant Howett in ''Film/CarryOnJack''. He hates being second-in-command to the wimpy Captain [[IronicName Fearless]], who turns away from an opportunity to fight the enemy the best that he can. When Howett eventually loses his thread with him, he and the rest of the sailors on their voyage organise a fake mutiny (with "unconscious" sailors covered in jam/blood) to scare the captain away, and he wins. [[spoiler:Unfortunately for him, Howett makes everything worse for the voyage, due to his greediness and BloodKnight mentality. Within at least 30 minutes of being in charge, the crew are arrested by the Spanish Armada and forced to work for them, in exchange for public execution.]]
* In ''Film/WarCraft2016'', when [[spoiler:Medivh is fully under fel's influence]], he convinces Llane that a rebellion among orcs is in full swing and that three legions will be enough to crush Gul'dan. He also pushes [[spoiler:Lothar]] further into SanitySlippage with some well-placed comments.
* In ''Film/TwoThousandOneASpaceOdyssey'' [[spoiler:HAL 9000]] is supposed to be omniscient guide for the rest of the Discovery crew, but after Frank Poole's death it is clear he no longer wants Dave alive.

* [[spoiler:Leigh Teabing]], the central villain (out of many candidates) in ''Literature/TheDaVinciCode''.
* Saruman in the ''Literature/TheLordOfTheRings'' books (and especially in the movies). Grí­ma Wormtongue also qualifies.
* Captain Dudley Smith in ''Literature/LAConfidential''.
* Chauncy in ''Literature/TheDresdenFiles''.
** This is also a big part of how [[OurDemonsAreDifferent the Fallen]] operate: If you pick up one of the [[ArtifactOfDoom Blackened Denarii]] you get an ancient, superintelligent and ridiculously powerful SpiritAdvisor who'd be happy to show you how to solve any problem you run into -- until you're so dependent on its help that it can control you completely.
* J.K. Rowling really likes this trope in the ''Literature/HarryPotter'' books.
** [[spoiler:Professor Quirrel]] in ''[[Literature/HarryPotterAndThePhilosophersStone Philosopher's Stone]]''.
** [[spoiler:Tom Riddle aka Young Voldemort]] in ''[[Literature/HarryPotterAndTheChamberOfSecrets Chamber Of Secrets]]''.
** Subverted in ''[[Literature/HarryPotterAndThePrisonerOfAzkaban Prisoner of Azkaban]]'' when [[spoiler:it looks like Lupin is one of these as well]].
** Although not canon, many fanfiction writers speculate that [[spoiler:[[TheQuisling Peter Pettigrew]] was the one who planted suspicions of Remus's loyalty in Sirius's mind.]]
** [[spoiler:Alastor Moody (Barty Crouch, Jr. disguised as him, to be precise)]] in ''[[Literature/HarryPotterAndTheGobletOfFire Goblet of Fire]]'', whom Harry and co. frequently consult for help solving the mysteries.
** ''[[Literature/HarryPotterAndTheHalfBloodPrince Half-Blood Prince]]'' [[spoiler:makes it look like Snape is one, too, only to invert it in [[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]].]]
* In Boris Akunin's ''Fiction'', we have Ivan Panteleevich, leader of an elite Soviet sports club. Sergei Dronov, one of the superpowered protagonists, was discovered and saved by him early in the book, and has followed "the Sensei's" advice ever since, leaving the life of crime and becoming a sports celebrity and a powerful businessman during the Perestroika. In the end, it turns out that the Sensei was [[spoiler:working for the GovernmentConspiracy all along -- and indeed is one of its leaders. What's more, Dronov remains loyal to him and is all too happy to join a secret superhero team for the conspiracy. To this we may add that, under the pseudonym of Alexander Aleksandrovich, he is also the father of another protagonist's daughter (becoming something of an advisor to him as well, though not nearly as trusted as in the first case), and brings that protagonist in as well, though he is more skeptical after being told the truth.]] Mind you, he's not ''necessarily'' evil, inasmuch as he seems to genuinely want to help Dronov and is mostly concerned with [[spoiler: fighting off an alien conspiracy that runs counter to the government conspiracy.]]
* The Oracle of delphi in the ''Literature/PercyJacksonAndTheOlympians'' series is this trope, just as she was in Myth/ClassicalMythology. Often she gives vague ExactWords style prophesies, or the heroes assume she's talking about one person, when she means another, after all she only speaks in prophesies, so she can't just tell them outright. [[spoiler:after she is finally released from her AgeWithoutYouth immortality and allowed to die, Apollo appoints Rachel Elizabeth Dare to be the new oracle. She still holds this position in ''Literature/TheHeroesOfOlympus''.]]
* In ''Literature/TheWinterQueen'' (an earlier Boris Akunin novel), there is Ivan Frantsevich Brilling, hero to and mentor of the protagonist, rookie detective Erast Fandorin. Fandorin is none too pleased to find out that Brilling is part of the evil conspiracy.
* Literature/RomanceOfTheThreeKingdoms has several, including one who served Liu Bei but was tricked into serving Cao Cao; he refused to give meaningful advice from then on and kept his mouth shut when he saw through the ruse at Chi Bi. More importantly, [[spoiler: it's the descendants of Sima Yi, Cao Cao's strategist, who ends up unifying the three kingdoms; one Cao son even gets ''murdered in broad daylight'' by the Sima clan]].
* In ''Literature/TheKingdomsOfEvil'': De Macabre for certain, and possibly everyone else in Skrea.
* [[spoiler:Dusk]] in Laini Taylor's ''[[Literature/FaeriesOfDreamdark Silksinger]]''.
* From ''Provost's Guard'' in the Literature/TortallUniverse, [[spoiler: Tunstall]], though only for the second half of the final book. He didn't ''want'' it to go so far, but it got out of hand, quickly.
* ''[[Literature/AMagesPower A Mage's Power]]'': For a good chunk of the story, Eric is a HeroicHost for the spirit of Dengel. He relies on the dead mage's advice and knowledge of magic to get out of scraps and accomplish goals. Then he finds out that Dengel is only bidding his time until he can [[GrandTheftMe take over Eric's body.]]
* ''[[Literature/DeltoraQuest Deltora Quest]]'' has a textbook example with [[spoiler:Mother Brightly]] in its TournamentArc, the Rithmere Games.
* In ''Literature/TheDragonWaiting'', Gregory uncovers evidence of a conspiracy at the English court and takes it to [[spoiler:the Duke of Buckingham]] -- who, unfortunately for Gregory, is in on it.
-->"Your Grace." He reached into his bag, produced the translation of Mancini's letter. "We have a great deal of trouble. I hope that these are men you can trust."\\
"Yes, Professor, they are absolutely loyal to me," [[spoiler:Buckingham]] said, and signaled for his men to close the door.
* In ''Literature/TheDragonHoard'', the sorceress Maligna arranges to become one to the heroes in order to prevent their quest from succeeding.
* In ''Literature/TheSpiritThief'', it eventually turns out that [[spoiler:Lenette]] has been poisoning her queen for years and is in fact a DeepCoverAgent for the Immortal Empress.
* In ''Literature/AScholarOfMagics'', [[spoiler:the apparent reasonable authority figure the Earl of Bridgewater turns out to be the villain behind the entire plot]].

[[folder:Live-Action TV]]
* In the ''Series/DoctorWho'' episode "[[Recap/DoctorWhoS11E2InvasionOfTheDinosaurs Invasion of the Dinosaurs]]", Sarah Jane Smith falls victim to this trope ''twice''. First, the man she sees for help finding the villains' base turns out to be the one who helped them set it up. Then, after she escapes from him, she takes what she knows to the general who is coordinating the state of emergency, not knowing that, while she was away, he had ''also'' been revealed as a member of the conspiracy.
* ''Series/GameOfThrones'':
** Many of Roose Bolton's moves become this in hindsight, such as sending the 500 men to Winterfell to supposedly take it back. They burn Winterfell in order to cover Roose's bases.
** Grand Maester Pycelle will work for the strongest side, who are House Lannister. Jaime, who used to be a bodyguard of the previous regime, recalls that prior to the Sack of Kings Landing by the Lannister armies, Pycelle advised King Aerys to open the gates to ensure them a victory, whereas Varys advised against it. He tries to do the same sort of scheming when Tyrion is acting as Hand of the King by going to Cersei behind his back. Since Tyrion is much smarter, he devises his own plot to uncover any disloyal advisors in the Small Council and subsequently strips Pycelle of all power and has him thrown in a cell.
* From ''Series/{{Heroes}}'': Claire has been hiding from her father the fact that she heals incredibly fast. She finally can't take the pressure anymore and decides to tell him... and he tells her he already knows, and asks her whom else she's told. Subsequently, every person she mentions has their memories of it wiped, and Claire herself is targeted for a wipe.
** In an ironic twist, though, HRG was trying to ''protect'' Claire (and the others) by doing this.
* ''Series/BuffyTheVampireSlayer'':
** [[Recap/BuffyTheVampireSlayerS3E7Revelations Gwendolyn Post]] (played by Serena Scott Thomas), the dark magician who poses as Faith's new Watcher.
** "Doc" (played by Joel Grey), seems to be a strange but mostly harmless old sorcerer/demon willing to help Dawn out, but turns out to be the closest thing to TheDragon to Glory's BigBad role in Season 5.
* [[spoiler:Boyd Langton]] from ''Series/{{Dollhouse}}''
* ''[[Series/TheFlash2014 The Flash]]'': [[spoiler:Dr. Wells turns out to be the Reverse Flash AKA the Man in Yellow. He is later revealed to be Eobard Thawne, who used a device to kill the real Dr. Wells and [[FaceStealer steal his identity]]]].
* [[spoiler:Digger]] in ''Series/JohnDoe''. However, WordOfGod is that it's a RedHerring ([[spoiler:it's not Digger but an enemy after a plastic surgery]]).
* [[spoiler:Harry Wolfe]] in Season 2, ep. 2 of ''Series/{{Life On Mars|2006}}''.
* Subverted in "[[Recap/StargateAtlantisS02E09Aurora Aurora]]", an episode of ''Series/StargateAtlantis'': When visiting the ruins of a ship that had the crew both in stasis and believing that they were still flying the vessel in a virtual reality setting, the second in command apparently was planning to do something against her boss. However, its later revealed that the actual second in command was killed long before the events of the episode by a Wraith, and a Wraith (presumably the same one that killed her) was impersonating her.
* ''{{Series/Merlin}}'' has Agravaine as a good example of this. Arthur's uncle and advisor, as well as TheMole. Merlin and the rest eventually figure him out, but Arthur takes the longest to quit trusting him.
* ''Series/{{Scandal}}'': [[spoiler: Cyrus, though he does have good intentions at times]].
* ''Series/{{Spooks}}'', Series 7: Bernard Qualtrough, a retired [=MI5=] spycatcher who Sir Harry Pearce calls on in the third episode, after realizing that Operation Sugarhorse, a plan to insert Western moles in high-ranking Russian government positions, is compromised. Harry has several meetings with him about likely suspects inside the Service who could be passing intel to the Russians, and he doesn't find out until the tail-end of episode five that Qualtrough himself is a long-term mole for them. By the next episode, Qualtrough has successfully framed Harry for the leak, in order to protect his real contact on the Grid -- [[spoiler:Connie James]].
* In ''Series/LegendsOfTomorrow'', Rip Hunter is revealed to have absconded with the ''[[TimeMachine Waverider]]'' against the orders of the Time Masters to try and stop Vandal Savage. His mentor then shows up and tries to convince Rip to go back, so the Time Masters can start repairing the damage to the timeline done by Rip and his team. Mick Rory, who has been listening in on the conversation, immediately tells him that the Time Master plans to betray and kill him, along with the rest of the team. Rip is reluctant to believe him, but he does bring backup during their next meeting. It turns out Mick was right. The Time Master shows up with the BountyHunter Chronos, who was paid to kill Rip and the others. Mick and Jax/Stein save him.

[[folder:Professional Wrestling]]
* At the 2015 ''Guerra De Reyes'', it was revealed all the problems faced by La Artillería Pesada in the World Wrestling League were caused by their manager, El Profe, who revealed this after he betrayed Thunder and Lighting to Jose Chaparro and Legion, handing Kronya and Spectro the {{tag team}} title belts.[[/folder]]

* [[spoiler: The Elder]] in Terranigma. Also [[spoiler: Yomi or dark side Yomi.]]
* From ''VideoGame/AssassinsCreedI'' [[spoiler: Al-Mualim is not only a Templar himself, but the BigBad.]]
* [=GLaDOS=] from VideoGame/{{Portal}}. "The Enrichment Center is required to remind you that you will be baked and then there will be cake."
* In both ''VideoGame/MetalGear'' and ''VideoGame/MetalGearSolid'', the player-hero receives advice via radio [[spoiler: much of which is revealed to come from each respective game's BigBad.]]
** In a variation, in '''three out of four''' ''Metal Gear Solid'' games, [[spoiler:TheDragon, Revolver Ocelot]], is advising and betraying the game's BigBad on behalf of a singular third party. How does he keep getting away with this? [[MagnificentBastard Impressively]].
*** ''Subverted'' in ''VideoGame/MetalGearSolid4''. Drebin [[spoiler:was put in place by the AncientConspiracy...in order to help Snake defeat the BigBad]]. He also makes it clear from the beginning that he [[WildCard works for everyone who can pay him]], and is telling the truth when he says he won't betray his customers, Snake included. He even saves the man's life on occasion.
* ''VideoGame/FinalFantasyX'' can be considered the apotheosis of the concept. The party's initial quest is a voyage to seek aid in destroying the monster Sin; [[spoiler: the ultimate end of this quest is the spirit of Lady Yunalesca â who, in TheReveal, turns out to be an insane nihilist who has been complicit with Sin's cycle of reincarnation since the beginning, having offered her own husband as the first Final Aeon (which would also make him the second Sin). And the Maesters of Yevon are being advised on how to defeat Sin by Maester Seymour, in [[TheReveal The ''other'' Reveal]], turns out to be an insane nihilist who is plotting to merge with Sin so he can destroy all life on Spira.]]
* In the first ''[[VideoGame/RatchetAndClank2002 Ratchet & Clank]]'' game, our heroes initially try to alert local superhero Captain Qwark to the Blargg threat, but discover that he's actually working ''with'' Chairman Drekk, who's offering him a substantial amount of money and fame for sponsoring their new homeworld.
* In the old C64 game ''[[VideoGame/TheBardsTaleTrilogy Bard's Tale 2]]'', the goal was to find the pieces of the Destiny Wand in order to defeat the big bad Lagoth Zanta. Every time you found a piece, you needed to get hints to the location of the next one by paying a character known as the sage. [[spoiler: Once you assemble the wand, you discover that the sage was in fact Lagoth Zanta all along.]] Incidentally, you can pay the sage for information about some things other than the pieces, and he ''does'' have accurate information for sale on the subject of Lagoth Zanta.
* ''VideoGame/{{Persona 2}}'' features a variation; in both games, the Time Count provides useful services -- ones that can't be gotten anywhere else in Eternal Punishment. He turns out to actually be an avatar of Nyarlathotep, the BigBad. Unlike most examples, it's not part of some overarching scheme -- being a trickster and manipulator, he decided it'd be more fun this way, and arrogantly believed that even if he helped them, the heroes couldn't possibly defeat him.
** In ''VideoGame/{{Persona 3}}'', [[spoiler: it turns out that Shuji Ikutsuki was actually trying to summon Nyx and end the world since long before the game even began, and that serving as the mentor for SEES was his way of using them as a weapon to accomplish this task. Without his own Persona, he had no way of defeating the Full Moon Shadows who needed to die in order to free Nyx, so he found some people who could get the job done, and...]]
* In ''VideoGame/{{BioShock|1}}'', [[spoiler: your guide throughout most of the game, former revolutionary figurehead Atlas, turns out to be mobster Frank Fontaine, who was thought dead according to the back story. You're [[TomatoInTheMirror a genetically-altered and hypnotically-conditioned assassin]] created by Fontaine as part of his scheme to seize control of Rapture from Andrew Ryan, and Atlas's CatchPhrase "Would you kindly..." was actually [[WordsCanBreakMyBones the command phrase to make you obey his orders.]]]]
* In ''VideoGame/{{Vexx}}'', [[spoiler:the player is given advice by an old mentor figure named Darby about finding the Wraithearts in order to eventually defeat the BigBad. Of course, Darby actually IS the BigBad with the EvilPlan.]]
* ''VideoGame/UltimaVII'' plays with this a bit by linking it to a ChainOfDeals. In order to contact the Time Lord, whose help is necessary to stop [[BigBad the Guardian]] from dominating Britannia, you need to get help from [[WillOTheWisp the Wisps]] -- interdimensional information-brokers who, in exchange for the help, want you to acquire information for another client of theirs. The information in question is a notebook on the Guardian and [[PathOfInspiration his puppet church, the Fellowship]], composed by one of the [[OnlySaneMan few Britannian scholars]] aware of the Guardian's existence. Turns out, their client ''is'' the Guardian, who, having found out what his opposition knows about him, then has him murdered.
* ''Franchise/FireEmblem'':
** In ''VideoGame/FireEmblemTheSacredStones'', the high-ranked [[spoiler: Paladin Orson leads Prince Ephraim and his group into a direct trap, having betrayed his country since the enemy promised to revive his deceased wife.]]
** In ''[[VideoGame/FireEmblemTellius Radiant Dawn]]'', [[spoiler: Izuka combines this with EvilChancellor and tricks [[NaiveEverygirl naive Prince Pelleas]] into selling out his country to the greedy Begnion senators. Those same Senators, in turn, betray and attempt to murder their own Empress for passing policy they don't approve of. Except for Sephiran, her closest and most trusted advisor and guardian... who betrays her for a ''different'' reason]].
** Exaggerated in ''VideoGame/FireEmblemAwakening'', Chrom randomly introduces a never mentioned character with a [[PaletteSwap re-colored]] {{Mook}} [[ReusedCharacterDesign design]], the Hierarch, in chapter 7. Chrom says the Hierarch was his elder sister Emmeryn's advisor and caretaker when she was young. Less then a Minute after this, the Hierarch walks over unseen to the enemy commander, tells him he led Emmeryn and her friends into an ambush, [[spoiler:the enemy commander then [[RewardedAsATraitorDeserves rewards him with death]].]] This event, and the Hierarch are both [[AbortedArc never mentioned again]], which becomes odd as the characters never learn he betrayed them in the first place, but [[ForgottenFallenFriend just forget about him]].
* In ''VideoGame/TalesOfTheAbyss'', [[spoiler:Van, the main character's mentor and pseudo-father figure, aids the party and [[TheMentor provides advice and counsel]] to the main character for the first third of the game. He then not only betrays the party and leaves them to die, but also turns out to be the BigBad. He manages to [[KickTheDog rub even more salt in the wound]] by casually telling the main character that, in fact, Van [[LukeIAmYourFather created]] him to be nothing more than an [[ReplacementGoldfish inferior duplicate]] of one his minions, to be sacrificed as a pawn in his plot to [[TheEndOfTheWorldAsWeKnowIt destroy the world]]. Ouch. The fact that Van turns out to be more of a NecessarilyEvil villain never alleviates the bitter sting of this [[EtTuBrute personal betrayal]].]]
* Subversion in ''VideoGame/SuperRobotWarsOriginalGeneration'', especially on Mizal Touval, the Shura Advisor (because, he is not on the player's side all the time). He actually had plans on his own, that is to overthrow the BigBad and usurp his power on his own. But he never got lucky in his endeavor, because: [[spoiler:He either gets killed before he could pull the treachery off (''Compact 3''), or said BigBad is dead first, and his successor killed him before he could do anything else (''Original Generation Gaiden'').]]
* In ''VideoGame/UnrealIITheAwakening'', the main character's rather paternal commanding officer sends him on a FetchQuest to assemble {{Plot Coupon}}s, ostensibly under orders from TheFederation to keep it out of the hands of the AlwaysChaoticEvil Skaarj. [[spoiler: It turns out he just wants the assembled ArtifactOfDoom for himself to take over the universe]].
* In ''VisualNovel/ApolloJusticeAceAttorney'', in the first case, [[spoiler:the eponymous attorney is working under Kristoph Gavin, who serves as his co-counsel in this case. Kristoph turns out to be the murderer. Then in the fourth case he turns out to be the Big Bad ''of the whole game''.]]
* ''Franchise/{{Castlevania}}''
** ''VideoGame/CastlevaniaOrderOfEcclesia'' has [[spoiler:Barlowe teaching Shanoa how to use glyphs and such, so she can use the Dominus glyph to destroy an artifact that, when destroyed, will allegedly destroy Dracula. He keeps secret from her two things: that using Dominus will kill the user ([[ViolationOfCommonSense you can even use it and die in regular gameplay, once you have all three parts]]), and that destroying said artifact, in actuality, will [[NiceJobBreakingItHero bring about the return of Dracula and his castle]], which was his goal all along.]]
--> [[spoiler:Barlowe: How dare you... even forget... who raised you... you... STUPID DISCIPLE!]]
** Zead of ''VideoGame/CastlevaniaCurseOfDarkness'' also qualifies as a Treacherous Advisor. At first, he is seen giving Hector helpful hints and advice in his quest to get revenge on Isaac for killing his wife. Naturally, St. Germain knows what Zead's true purpose is, thus why the two are enemies with one another as Germain himself tries to stop Hector from going after Isaac and therefore playing any more of his role in Zead's plans. Eventually, it is revealed that Zead was using Hector to find a perfect host for the resurrection of Dracula, and that, indeed, Zead was Death, TheDragon to Dracula himself, [[MasterOfDisguise in disguise]].
** ''VideoGame/CastlevaniaLordsOfShadow'' had Zobek, not put in spoilers because the cast is ever so small, who else could it be? He turns out to be [[spoiler: one of the eponymous Lords of Shadow and heavily implied to be [[TheGrimReaper Death]], but before he can usurp the mask's powers SATAN kills him.]]
** In ''VideoGame/CastlevaniaLordsOfShadow2'', the aforementioned Zobek [[spoiler: ''is'' confirmed to be [[TheGrimReaper Death]].]]
* In ''VideoGame/SystemShock2'', [[spoiler:the voice of Dr. Janice Polito is played by very special guest star... [[OhCrap SHODAN]].]]
** [[spoiler:Who then forms a [[EnemyMine fragile alliance with the player and guides them against]] [[BodyHorror The Many]]. [[ChronicBackstabbingDisorder No prizes for guessing how this one ends]].]]
* ''VisualNovel/PrincessWaltz'' features a [[NightmareFuel really disturbing one]], [[spoiler:when the dizzy, cute, HaremNanny April turns out to be stone cold evil... [[DissonantSerenity and doesn't change her mannerisms or expression!]]]]
** Or [[spoiler:not. Ending suggests she was good all along, and possibly the heroes strongest ally. She might have been lying, of course, she was certainly capable of that]].
* [[spoiler:Your boss, Mr. Jones]] in ''VideoGame/CodeNameViper'' is actually the guy behind the South American drug ring you've been commissioned to stop.
* In ''VideoGame/{{Mantra}}'', the plot of the game is that Saric (the player character) is supposed to retrieve the Mantras of [[ElementalRockPaperScissors fire, earth, water, air, and force]] to help out his master, the Ambassador, in his negotiations with the evil magician Balther. Late in the game, however, you find out that [[spoiler:the Ambassador is actually Balther]].
* Subverted by [[spoiler: Mr. Mach]] in ''[[VideoGame/MegamanBattleNetwork Rockman.EXE]] 6'', as he is not truly treacherous. [[spoiler: After Rockman is lured into a trap by WWW ([[OddlySmallOrganization World Three]]) and kidnapped, several members decide to betray WWW and start up their own organization, taking Rockman with them.]] He then arranges a meeting with Netto to explain [[spoiler: that he has actually been working for WWW in order to repay a favor from a higher-ranking member, his involvement in the near burning of the school during the first day, and that he helped kidnap Rockman before finding out about the traitors. Mr. Mach then tells Netto where Rockman might currently be, verbally beats himself up for being a hypocrite, and asks for forgiveness before leaving.]]
* The original ''{{Mercenaries}}'' has Josef oust Sergei as leader of the Mafia near the end of the game; probably not all that surprising, since 1) this is TheMafiya we're talking about, 2) Sergei is an airheaded SmallNameBigEgo, 3) Josef is ex-KGB, and 4) Sergei tried to have the player character ''and'' Josef taken out by the North Koreans first, which obviously failed 5) they foreshadow the hell out it by showing Josef having practically undisguised contempt for Sergei's bumbling and snotty attitude.
* In ''VideoGame/BunnyMustDie'', Bunny, upon receiving her curse, meets up with a fat messenger of God ([[spoiler:read: Dechronos]]) who offers to lead her to the Cave of the Seven Devils to remove said curse -- and gets gored by a stag shortly upon their arrival. By the time she's slagged all the other devils and beaten Chelsea to a pulp, she finds him, fresh as a daisy, and he tells her that he set the plant to blow once she was near it. All of this just to give her a reason to get him all his power back.
* King Lemele in ''VideoGame/The7thSaga''. [[spoiler:Or, rather, the ''BigBad'' Gorsia, who had already killed Lemele and was impersonating him when the game started.]]
%%* [[spoiler:Grumpos Matavastros]] in ''VideoGame/{{Anachronox}}''.
%%* [[spoiler:Darth Vader]] in ''VideoGame/TheForceUnleashed''.
%%* [[spoiler:Tapir]] in ''VideoGame/{{Cocoron}}.''
* In ''VideoGame/ModernWarfare 2'', [[spoiler:General Shepherd, the main US Army commander, is TheChessmaster and ultimate BigBad, having manipulated the massive invasion of Washington DC and the war between the US and Russia to demonstrate the US's military might as revenge for having 30,000 of his troops nuked in the first ''Modern Warfare'']].
* [[spoiler: Kor]] in ''VideoGame/JakIIRenegade'' is the Metal Head Leader.
* Sindri Myr to Chaos Lord Bale in ''VideoGame/DawnOfWar'', leading to one of the most {{narm}}-filled moments outside of the Soulstorm expansion.
* In ''VideoGame/{{Okami}}'', you wind up consulting High Priestess Rao for help fixing the cursed mess that is Sei-an City and the Ryoshima Coast. Too bad she'd been killed months earlier, and you turn out to have been dealing with Demon Lord Ninetails, who was responsible for a lot of it and had been trying to use you as a MacguffinDeliveryService for the [[ArtifactOfDoom Fox Rods]] or, failing that, get you killed. It works pretty dang well, too, and only some very quick thinking and a HeroicSacrifice on Queen Himiko's part allow Ammy to stop Ninetails.
* In ''VideoGame/{{Psychonauts}}'', [[spoiler: Coach Oleander]] is the real Big Bad behind Doctor Loboto.
* In ''VideoGame/WarioLand 3'', Wario gets advice from a sealed away mysterious figure, who will apparently give him riches and power if released. But sadly for him, it turns out this figure is actually Rudy the Clown, a MonsterClown who conquered said pocket universe the game is set in, and transformed all the people into monsters.
* In ''VideoGame/{{Sacrifice}}'', [[spoiler:Mithras, a blind prophet and benevolent advisor to the gods is revealed to be EldritchAbomination Marduk in a cunning disguise.]]
* In The Settlers 7 campaign, Princess Zoe is sent by her father to save the kingdom of Tandria from the evil Lord Wolverine who usurped the good King Balderus. She is assisted by a kind old barkeep who [[spoiler: is actualy [[BigBad King Balderus]] in disguise. As added insult to injury, Wolverine usurped Balderus because he was a Tyrant and Balderus told Zoe that she was helping to free the people from Wolverine's evil rule.]]
* ''Many'' of these in ''VideoGame/AlphaProtocol'', but the gold medal goes to [[spoiler:the ''entire'' staff of the eponymous agency. There's no [[TheMole mole]]; ''everyone'' was complicit in the decision to abandon and kill you in Saudi Arabia.]]
** Well, actually, [[spoiler:there was a mole. Said mole was a mole against the entire remaining staff and saved your life by declaring you rogue and thus forcing you to fight the agency and Halbech.]]
* In ''VideoGame/DarkStarOne'', [[spoiler:Robert]] give Kayron his father's eponymous ship and sends him on his quest. In the end, he turns out to be Kayron's father's killer.
* In ''VideoGame/AsurasWrath'', [[spoiler:the Golden Spider]] offers Asura cryptic advice several times in the game [[spoiler:while he is in Naraku]] to aid him in his battle against the Deities. [[spoiler:The Spider is actually the BiggerBad behind the rise of the Gohma (and consequently the Deities' villainy as well) which was apparently a test of the Deities' worthiness to wield Mantra, and he's only aiding Asura because he wants to claim Mithra as his vessel and is grooming him to be his heir.]]
* Luigi has [[HeroOfAnotherStory an offscreen adventure]] in ''VideoGame/PaperMarioTheThousandYearDoor'' where he collects the pieces of The Marvelous Compass to rescue Princess Eclair under Minister Crêpe's guidence. [[spoiler:Minister Crêpe reveals himself to be an EvilChancellor who set up the princess's kidnapping to [[MacGuffinDeliveryService make Luigi rebuild the compass]] for his own nefarious purposes.]]
* Lloyd is one of these in ''VideoGame/TheLegendOfDragoon'', posing as an advisor to King Albert while secretly working for Emperor Doel, though this is only a secret to the characters; the player learns of Lloyd's deception in the very first cutscene in the game.
* Ghaleon in ''VideoGame/LunarTheSilverStar'', who turns out to be the BigBad.
* A variation in ''VideoGame/PokemonBlackAndWhite'': Since the theme of the game is GrayAndGrayMorality, the main antagonist N is the hero whose advisor turns out to have been using him all along, rather than the player character.
* In the first ''VideoGame/BookwormAdventures'' game, [[spoiler:Professor Codex appears to be happy to help Lex the bookworm rescue [[DistressedDamsel Cassandra the oracle]]. However, Lex learns that the BigBad who kidnapped Cassandra wasn't {{Dracula}}, as Codex told him, but Professor Codex himself, who used his imprisonment of Cassandra (and Dracula's apparent kidnapping of him) to maneuver Lex into fighting the books' monsters and unknowingly breaking the chains of fiction that kept them in the books. Thanks to Lex [[NiceJobBreakingItHero doing such a great job]] with these monsters, Codex can now control them as his minions.]] Fortunately, he gets a final boss battle to set things right.
* In ''VideoGame/SuikodenI'', one of the first characters to join you is CoolOldGuy Sanchez, one of the members of LaResistance under Odessa. He generally comes across as a fairly unremarkable [[SmartGuy Smart]] NonActionGuy, right up until the point he, well, lands himself on this page by revealing [[TheMole he was reporting to the Emperor the whole time]].
* Amethos from ''VideoGame/UnluckyHero'' seeks to kill off the younger princess of the kingdom, so that he can marry the ruling princess and take over. This happens in basically the first ten minutes of the game, so it's not really a spoiler.
** After his defeat, Lord Tourma fakes a HeelFaceTurn and acts as advisor. [[ObviouslyEvil No one's fooled]], except [[WideEyedIdealist Princess Christel]].
* Glade from ''VideoGame/BeyondTheBeyond'', full stop. His character portrait makes him look so transparently evil that the only people who probably didn't see it coming were under the age of 10, or maybe it was their first RPG or something. Bonus points for him losing his shit and transforming into a monster before the also-obvious boss battle.
* In ''VideoGame/RuneScape'''s "Rune Mysteries" quest, [[spoiler: Ariane's]] kindly and supportive mentor [[spoiler: Wizard Ellaron]] has been stringing her along in order to use her to blow up the Wizards' Tower.
** One of the Signature Heroes, RetiredBadass Xenia, is in her own mind a [[TricksterMentor Trickster]] SinkOrSwimMentor. To the player's perspective (and likely that of other characters involved), she's a treacherous advisor who places total strangers into certain peril in hopes that an adventurer (usually another total stranger) might step up and save them. She ''insists'' that she would be able to save the "victim" should the "rescue" attempt go wrong...
* ''VideoGame/PonyIsland'': [[spoiler:Subverted. The Daemons tell you the Hopeless Soul isn't to be trusted, and if you collect all the tickets...he still does absolutely nothing to seem he isn't on the up-and-up, he just decides to become the TrueFinalBoss to give a satisfying conclusion to the completionist run.]]
** Played straight, actually. [[spoiler: After you beat the game then tamper certain variables in the save file, come back into the game and hit continue will lead you to a screen where the typical 'devil head' sprite will appear blue and talk first with the sound effect of Lucifer, berating the player messing with game files, but afterwards switching to the sound......of the Lost Soul. Then it will let you in on a secret -- sometimes he talks "in different voices", and he asks you to "not to tell [[{{God}} dad]]".]]
* In ''VideoGame/WorldOfWarcraft'' the troll Yeh'kinya guided players through deciphering a prophecy about the return of Hakkar the Soulflayer and how to seal him away. Under his guidance players confronted the weakened soul of Hakkar and sealed it in an ancient vessel, supposedly to bind him. In fact Yeh'kinya knew that sealing Hakkar into the vessel was a necessary step to allow his rebirth, leading to Hakkar's rise in Zul'gurub.
** Drakuru in Grizzly Hills seems like a reasonable troll compared to his bloodthirsty kin so helping him in fighting them off seems like the smart move. In fact his directions resulted in the trolls losing control of their main defense against the Scourge, hastening their empire's fall and gaining Drakuru praise from the Lich King.
** Wrathion became this for Horde players in ''Mists of Pandaria''. He sent them to defeat Garrosh to "save the Horde" while fully believing the Alliance would subsequently subjugate it. He's rather dismissive of whatever complaints the player might have had about being used.
** On the Timeless Isle Kairoz had players empower his Vision of Time to see visions of the future if either the Horde or Alliance proved victorious. In a subsequent novel Kairoz used the Visions to allow Garrosh's escape to Draenor, intent on using the Vision to build an army across multiple timelines.
* ''VideoGame/FullThrottle'' had Adrian Ripburger, who murders his employer Malcolm Corley in order to kill biker culture by turning the world's last dedicated motorcycle manufacturer into a maker of minivans. What sets ''Full Throttle'' apart from most examples of the trope is that ''Full Throttle'' actually spells out the reason Corley keeps Ripburger around. Corley is primarily a visionary and idealist, but a self-aware one, who realizes he needs someone with business savvy and killer instinct (like Ripburger) to keep him from chasing too many wild dreams and running his company into the ground. Corley also makes no attempt to hide his personal loathing for Ripburger, though he claims to respect him on a professional level.
* ''VideoGame/RandalsMonday'': [[spoiler:The business bum is using Randal to regain the power of the ring.]]
* In ''VideoGame/TheNightOfTheRabbit'' some characters insinuate that the Marquis de Hoto, mentor to the protagonist, has malevolent intentions. [[spoiler: Subverted: he does not. However, he is also only a ''memory'' of the real Marquis de Hoto as he was before a FaceHeelTurn, so the concerns were not exactly ill-founded]].

* In ''Theatre/{{Pippin}}'', the [[spoiler:Lead Player is deliberately guiding Pippin down a path that is supposed to end with Pippin's dramatic suicide.]]

* Miranda West in ''Webcomic/TheWotch'' may qualify for this, given that she's keeping some very big secret from protagonist Anne and that she's willing to totally destroy the lives of a few people in order to make sure nobody interferes.
* ''Webcomic/{{Panthera}}'' has Reynder/Ari, who turns out to be [[BigBad Oosterhuis]].
* In Webcomic/{{Pibgorn}}, [[http://www.gocomics.com/pibgorn/2005/01/22/ a succubus can see that our heroes still find him useful]].
* Nicodemus, the BigBad of ''Webcomic/TheDreamlandChronicles'' got his start as one of these. Notably, he actually ''told his liege in advance that he would betray him'', though he made it clear that he would only do so if his liege continued what Nicodemus considered to be a self-destructive policy. His liege didn't stop. Nicodemus was true to his word.

%%* [[spoiler:Longarm/Longarm Prime/Shockwave]] in ''WesternAnimation/TransformersAnimated''.
* In ''WesternAnimation/ExoSquad'', Barca plays this role in his attempts to get Halis to assassinate Simbacca.
* In the ''WesternAnimation/MenInBlack'' AnimatedAdaptation, Kay's first partner and mentor Alpha turned out to be a scheming bastard. When Kay refused to join him, Alpha shot him and left him for dead. It's no wonder Kay became an emotionless robot after that.