Deceptive Disciple

The Deceptive Disciple gives the impression he is faithfully and respectfully following the teacher of whatever Way is being taught, but in reality he has his own agenda and will end up betraying both the teacher and the Way. The "Way" can be anything -- magic, religion, martial arts, business methods, governmental policy, or any combination of these things.

Compare Bastard Understudy, A Pupil of Mine Until He Turned to Evil (the pupil actually was good before), and The Paragon Always Rebels. A Merlin and Nimue pairing is likely to have this character.

Anime and Manga

 * Yu-Gi-Oh! GX: After his Freak-Out, Kaiser Ryo Marufuji defeated his old mentor and stole one of those dangerous forbidden decks, but the sad part is Sameshima incorrectly thought he was in there somewhere.
 * Sasuke from Naruto after the Time Skip. In his case, he's simply after power and, after being apprenticed to Orochimaru, . Whether he does it out of sheer contempt or to avoid his Deal with the Devil is left as an exercise for the reader.
 * He suggests that he would give his body to Orochimaru if it would help get revenge on Itachi, but after realizing that he's become stronger than Orochimaru, decides not to go through with it, so it's a mixture of both.
 * Inverted in Fist of the North Star: Souther's master tricked him into killing him, since There Can Be Only One master of Nanto Ho'Oh Ken at any time. Souther, who was actually very fond of his master, promptly goes insane with grief and becomes hellbent on building his master a tribute...in the form of an insanely large pyramid that is built with children as slave labor. He also forces a blind guy to set the capstone, or else.
 * from Mobile Suit Gundam 00.
 * As with many of his traits,
 * Cruelly subverted in Saint Seiya. Ikki did respect his master, Guilty, despite the horrible Training From Hell that the other put him through with full intention of having Ikki killing him no matter what the boy thought or felt.
 * Played straight with Ohko and Libra Dohko, though Ohko was more of a Jerkass than anything.
 * And again subverted with
 * Hyunkel in Dai no Daibouken is evil but becomes Aban's disciple to avenge his father.
 * Rando of Yu Yu Hakusho apprenticed himself to a notable psychic, learned his master's techniques, then murdered his master and used the techniques to go on a killing spree. Ninety nine times. Yusuke defeated him as he attempted to make Genkai Master Number One Hundred.

Comic Book

 * Baron Mordo from the Marvel Universe attempted to kill his teacher, the Ancient One, and ended up as the main nemesis of the Ancient One's star pupil -- Doctor Strange. There's overlap with A Pupil of Mine Until He Turned to Evil, but the Face Heel Turn (if there was one) happened long before Strange entered the picture.
 * It should be mentioned that the Ancient One even knew of Mordo's planned betrayl. It ended up being a Secret Test of Character for Strange since he was still a Jerkass at this time who had no magic skill, yet was planning to defy Mordo in the face of certain death.
 * In The Tick (animation) comics, Shing was once leader of all ninja operations in America before he was ousted by a student with less skill but more business sense. Shing recruited and trained a young woman named Oedipus to return the ninja to their former glory, in a parody of Daredevil's Stick/Elektra storyline.
 * Tron : Betrayal (a prequel comic to Tron: Legacy) indicates that while Flynn thought Clu was A Pupil of Mine Until He Turned to Evil, the truth was closer to Clu being a bastard all along. This is clearest when it's shown that he  and changes the Games into lethal contests. Flynn had been too overwhelmed with analog-world responsibilites to notice until it was much too late.

Film

 * According to the Expanded Universe, this is pretty much the only method of Career Advancement for the Sith in Star Wars.
 * A weirdly annoying subversion cropped up in Legacy of the Force. After spending years showing how Jacen Solo's curiosity, training, and raw Force talent taught him all kinds of useful tricks that other Jedi couldn't do, the series has him seeing through the Force that doing one thing will result in him killing his uncle, his teacher--which he does not want to do. So he goes the other way...and turns dark anyhow. You Can't Fight Fate, apparently (though he didn't end up killing Luke).
 * Palpatine/Darth Sidiousis an inversion, who instead deceives and abuses his disciples. The Expanded Universe reveals that Palpatine never intended to be replaced by an apprentice at all; rather, he concocted a complex scheme to achieve practical immortality through the use of clone bodies. Taking on apprentices seems to be somewhat of an amusing diversion to him.
 * Elle Driver/California Mountain Snake from Kill Bill eventually assassinates her old master, Pai Mei, and ends up facing his star pupil, The Bride/Beatrix Kiddo. Meanwhile, Beatrix herself is on a mission to kill her other former master, Bill, though the Bride's mission is more about vengeance than anything else.
 * In the 2005 CGI film Robots, Ratchet (Greg Kinnear) has sidelined and usurped the power of robot patriarch Bigweld (Mel Brooks).
 * Trumpy (Terrence Howard) in the Outkast musical film, Idlewild. He
 * Inverted in Batman Begins. Bruce Wayne is the Deceptive Disciple, but the League of Shadows are evil Knight Templar murderers. (This is debatable as Bruce initially joined the League with the intention to legitimately lead them in fighting corruption. It was not until he was asked to kill a criminal or himself be killed that he betrays the League.)
 * Storm Shadow in G.I. Joe: The Rise of Cobra. It's implied he turns on his master for feeling the foreign student, the kid who becomes Snake Eyes, is more talented than him.
 * Even though the Rise of Cobra version implies this, it's unconclusive. However, the G.I. Joe: Resolute version of Storm Shadow definitely follows the trope.
 * Tommy "The Machine" Gunn in Rocky V.
 * Prince Einon in Dragonheart, who only pretended to follow Bowen's code to learn how to fight, completely ignoring the knight's "Old Code".

Literature
""He that hath a Gospel Whereby Heaven is won (Carpenter, or cameleer,Or Maya's dreaming son), Many swords shell pierce Him, Mingling blood with gall; But His Own Disciple Shall wound Him worst of all!""
 * The Dark Elf Dalamar pretty much made a career out of betraying his master, Raistlin, in the Dragonlance series. Admittedly, Raistlin wasn't what you'd call benevolent, but still...
 * Raistlin himself is an even better example. After having gained power and knowledge from the ghost of the undead evil archwizard Fistandantilus, Raistlin became the next Master of Past and Present. He then traveled into the past to usurp all of Fistandantilus powers by going back to a time when the man was still mortal and posing as one of Fistandantilus' own apprentices. When Fistandantilus tried to suck out Raistlin's lifeforce and take over the young man's body to extend his own life (as he used to do with his apprentices), Raistlin killed Fistandantilus instead and took his place in history; fittingly Raistlin used Fistandantilus' own talisman to suck out the evil mage's lifeforce and improve his (Raistlin's) own frail health.
 * Of course, he then found out that he was karmically locked into following Fistandantilus' path through history, until he finds a cosmic loophole that allows him to change the timeline.
 * Sauron from The Lord of the Rings got the elves to teach him how to make Rings of Power, then made the One, and we all know how that turned out.
 * In the superb fanfic Morlindale, they deceived him in turn by taking off the rings at the moment when them wearing them would have given Numenor the victory over the Valar.
 * In Ben Jonson's Volpone, Mosca pulls the rug out from under Volpone by using the old swindler's techniques against him, showing that taking the greedy impulse to its logical extreme means living for onesself and onesself only, to the exclusion of even each other.
 * In Wolf of the Plains, as soon as Yesugei dies, Eeluk announces that he is the new khan and kicks Yesugei's family out of the clan to prevent them from stabbing him in the bacl, leaving them to die of hunger and exposure. Unfortunately for him, one of Yesugei's sons will grow up to become Genghis Khan. Oh, and this actually happened.
 * In The Warlord Chronicles.
 * In the Forgotten Realms novel The Crystal Shard, the incompetent wizard Akar Kessel murders his master, Morkai the Red, in order to usurp his position. The situation here is slightly more complicated than usual, as he is goaded into this by his master's colleagues, betrayed by them and left to die in the snow, and then finds an Artifact of Doom that makes him an aspiring Evil Overlord almost overnight.
 * Harry Potter series Big Bad Voldemort played the role of an upstanding and gifted student during his time at Hogwarts back when he still used the name Tom Riddle. All while recruiting like-minded students who would become the first Death Eaters, probing the secrets of the school, researching methods of achieving immortality, and engaging in acts of villainy such as killing Myrtle and framing Hagrid for it. The only staffmembers Tom didn't have completely fooled were Dumbledore, who saw enough of his true nature when he picked Tom up from the orphanage, and maybe Slughorn, who never saw Tom in quite the same light after he asked too many questions about Horcruxes.
 * In the Dale Brown novel Act of War,  turns out to be this, pretending to believe in Ruiz's eco-terrorist goals until the time is right to take over and switch to full-blown terrorism. He's not The Starscream because his treachery catches both Ruiz and readers by surprise, nor a Bastard Understudy because Ruiz is something of a Wide-Eyed Idealist who's more Well Intentioned than Extremist in Well-Intentioned Extremist.
 * The Rudyard Kipling poem "The Disciple" is about such people, and how often they pop up in religion.


 * In Robert E. Howard's Conan the Barbarian story "The Tower of the Elephant", Yara imprisoned and tortured his mentor who would teach him only White Magic voluntarily.
 * In the Star Wars Expanded Universe, Luke Skywalker sets up a Jedi academy. One of his first set of pupils, Brakiss, intended to be this. He was an Imperial plant with a lot of baggage in his background. Luke knew about this and thought he could change him - and it looked like it was working, Brakiss was Becoming the Mask. Then Luke put him through a mental test of himself that went too far and traumatized his pupil, who fled. In The New Rebellion, Brakiss largely unwillingly works for Kueller, A Pupil of Mine Until He Turned to Evil. Luke still thought he could be saved, and writing from Brakiss's POV suggest that he'd like that, but it's not to be. He dies in Young Jedi Knights.

Live Action TV

 * Turlough from Doctor Who was not exactly an apprentice, but he was one of the Doctor's two or three companions. For much of his time on the TARDIS Turlough was working for the Black Guardian, although he eventually sided with the Doctor when his betrayal came to light, and was forgiven.
 * Turlough is an interesting case, because he is recruited as an infiltrator under false pretenses, and struggles for a while with which side he's on. Eventually,
 * One of the Immortals on Highlander the Series used this as a tactic- she'd impersonate a new Immortal, get someone to 'mentor' her, and use that as a chance to learn their weaknesses and/or new methods. Then, she'd behead them.
 * In another episode immortal in a kid's body used his youthful looks to pull this off.
 * Kamen Rider Ryuki: Kagawa Hideyuki has impressed on his student, Toujou Satoru, that a hero must be prepared to sacrifice things. Toujou takes the consequence of this and.
 * Anubis pulled one of these on Oma Desala, pretending to be different from other Goa'uld so she would help to ascend, and then revealing his true intentions once he got what he wanted.
 * Tahleen in the Farscape episode "Rhapsody In Blue", who approaches Zhaan, asking to be taught how to control her darker impulses; when Zhaan agrees, Tahleen quickly realises that she doesn't have the time to learn the technique through normal tuition, so she simply tears the information out of Zhaan's mind, driving her insane in the process.

Music

 * The viewpoint character from The Police's song "Wrapped Around Your Finger" is this, and promises to "turn your face to alabaster/when you find your servant is your master."

Tabletop Games

 * In Hero Quest (a board game that could be described as tabletop RPG lite and which the Warhammer Fantasy Battle world was loosly based on) the Big Bad is a Evil Sorcerer and Chaos Lord called Morkar who gained his powers by secretly reading up on all his master's forbidden advanced magic stuff before running away. At least he didn't kill his master at that time.

Video Games

 * Xehanort/Xemnas/Ansem from the Kingdom Hearts series was the apprentice of Ansem the Wise, and continued Ansem the Wise's research into the "Heart of Worlds" after his master had realized the dangers implicit in it, and forbidden it. After banishing Ansem to the realm of nothingness, Xehanort took his master's name as his own, continued the research - and promptly ended up as a Heartless. His "Nobody", Xemnas, gets to confront Ansem the Wise towards the end of Kingdom Hearts II, and even at this point, he maintains that he was right in continuing the research.
 * All of the founding members of Organization XIII were of this variety, following Xehanort, but Braig/Xigbar pulls this twice. Xehanort and the others were loyal until Ansem interfered with their research and for most of them it's implied that the research on Darkness itself caused these feelings, but Braig is shown in Birth By Sleep to have been out to dethrone Ansem the Wise from the get go, long before Xehanort and the research came into the picture and for no real reason beyond being evil it seems.
 * Knights of the Old Republic gives the player a suspicious dialogue option upon first becoming a Jedi apprentice, in which he can lie that he intends to follow the light side (this is distinguished from the truthful equivalent option with the [lie] prefix).
 * In the sequel, Kreia outright encourages this behavior, telling the Exile to take anything useful from her teachings, then discard her when she has outlived her usefulness.
 * Akuma/Gouki from the Street Fighter series murdered his master, Goutetsu, in order to master the Shun Goku Satsu technique. This is a subversion, however, since Goutetsu deliberately taught him the technique, and was actually happy that Akuma killed him, since the only way to fully embrace the "Killing Intent" which powers the Shun Goku Satsu is to give up all compassion.
 * In the adventure game Full Throttle, the nice CEO Malcolm Corley is killed by his VP, Adrian Ripburger, who wants to turn Corley Motors' motorcycle production-lines into making minivans -- and money.
 * People in Bioware games seem to live for this: it happens in KOTOR 1 and 2, Jade Empire and at least one of the Neverwinter Nights games.
 * Jade Empire plays this straight with the Disciple Gao (though he barely even tries to keep up any deception) but later inverts it:
 * Frost betrays her Sifu Sub-Zero in her ending to Mortal Kombat Deadly Alliance. However she severely suffers the consequences.
 * In Fire Emblem: Path of Radiance/Radiant Dawn was one a student of Greil's.
 * In Metal Gear Solid 2, the villainous Mad Bomber Fatman turns out to be a former student of your friendly neighborhood Bomb Disposal Technician, Peter Stillman. Apparently, Fatman decided that it was more fun to use his intimate knowledge of the inner working of bombs to MAKE them, rather than disarm them... and, as any Deceptive Disciple would want it, he eventually kills his mentor with one of his bombs.
 * In Dragonfable, . At first it's played for laughs, given   rather ineffectual efforts. Then.
 * Near the end of Pokémon Platinum,  takes over Team Galactic and goes into a Motive Rant about how the team's original plans were pathetic and how immature and foolish  were for wasting their potential.
 * In Castlevania Order of Ecclesia Albus steals the Dominus glyph that was supposed to be able to defeat dracula, apparently annoyed the far less experinced Shonana was chosen over him
 * Feng Wei, introduced in Tekken 5, was a Deceptive Disciple in his backstory. He killed the dojo master who raised him from childhood because he felt slighted after his master scolded him for picking fights outside the dojo, and only joined the tournament because he wants to steal back what the Mishimas stole from his master and use it for himself.
 * One of the Nameless One's past incarnations in Planescape: Torment did this. In order to progress, you have to find someone able to read a very specific language. The only known person able to do so has been dead for a long time. Upon eventually contacting his spirit, he relates a story of how he taught it to one student, and that this student turned around and murdered him afterward. It's masterfully done; while he's telling the story, you're remembering killing him, and when it's done, you recall the language.
 * in Henry Hatsworth in the Puzzling Adventure is this, stating that
 * in Luminous Arc. tries to betray  The heroes stop this from happening, however.

Web Original

 * Moira Vu Noi in The Gungan Council. While Sith are meant to perform this eventually, she managed to keep the ruse that she would blindly follow Darth Apparatus until after her trial on Kesh.

Western Animation

 * In the backstory for the original Animated Adaptation of the Teenage Mutant Ninja Turtles, Shredder and Splinter, who was then known as the human master Hamato Yoshi, originally studied together as pupils in the Foot Clan. After framing Yoshi for attempted murder by pinning his dogi to the wall with a dagger (so that when he pulled it out, the others would draw the wrong conclusion) and forcing him into exile, Shredder, who was then known as Oroku Saki, took control of the Foot Clan (by unknown means) and turned it into the evil band of ninjas that we know today. His relationship with Splinter closely matches the evil student/good student version of this trope.
 * Batman Beyond had multiple instances of children betraying and causing the death of their parents, and getting away with it. However, Batman always paid a visit to remind them that they usually don't stay dead. However, in both instances,
 * Bubbles from Chip 'N' Dale Rescue Rangers uses the Cola Cult's belief in "fizzing" away all their worldly goods to gain said goods... under the nose of the kindly, well-meaning leader.
 * Happens in one episode of Jackie Chan Adventures when
 * Valmont does this in another episode where he spends time at a monastary training with some monks with the intention to get the directions to a secret treasure from its leader.