The Big Bad has an assistant or sidekick that they spend a lot of time bragging to about just how clever they are. Near the end, their assistant double crosses them spectacularly while their back is turned. Essentially, this is Deceptive Disciple, except that the Bastard Understudy is apprenticed to an Evil Mentor.
In many cases the Bastard Understudy appears to have been groomed as a successor of sorts. While the Big Bad hates the idea of defeat, they know they are not going to live forever, and the Bastard Understudy offers a continuation of their legacy. A sublime game of Gambit Roulette keeps the Bastard Understudy just out of reach of the power... until the last play.
The Starscream is a visible rival who lacks the Bastard Understudy's loyalty and patience. The Dog Bites Back is when the betrayal is not premeditated. May be a form of Thanatos Gambit. See Magnificent Bastard, Manipulative Bastard, Villain Takes an Interest, and The Chessmaster for characters who are likely to have one of these around.
- Code Geass: This is the modus operandi of the Big Bad Social Darwinist Emperor. By raising a family of Bastard Understudies and then encouraging them to plot and scheme against each other- and even himself- over the throne, the Emperor hopes to produce a strong leader for Britannia. If Lelouch is anything to go by, his methods are quite effective.
- And the trope itself plays out with Schneizel and Charles. Scheizel prepares to assume command of Britannia and leaves Charles on his own. However, Lelouch killing Charles forces Schneizel to go into hiding.
- "Fucking Ribbons" Almark in Mobile Suit Gundam 00. He appears to be a harmless toady of the apparent Big Bad Alejandro Corner, only to reveal himself as the key villain while Celestial Being kills Corner at the end of Season 1.
Alejandro Corner: RIBBONS!
- In Naruto Kabuto and Sasuke represent the two different types of this: the latter learns all he can from Orochimaru and then "kills" him, while the former, after witnessing Orochimaru's death, has become obsessed with carrying on and perfecting his legacy.
- To be fair to Sasuke, in this particular case he acted out of principle- he might have planned on dumping Oro from early on, but he only killed him because he saw Orochimaru as an evil, sadistic psychopath who had abandoned whatever higher purposes he once pursued, every bit as bad as the mass murdering brother he was training to kill. Which is exactly right, despite the irony that Sasuke himself has currently begun turning into exactly that type of person.
- Katsumata in 20th Century Boys, who takes advantage of Fukubei/Friend's Thanatos Gambit plan to kill him for real and take his place on the viewing platform.
- In the Hentai Bible Black Origins, Kozono Nami is this to Takashiro, the original leader of the coven of witches. When Takashiro is rendered comatose, Nami uses the position to take over. When Takashiro tries to get the coven to disband, Nami completes her usurpation.
- Inverted in The Metabarons, where the heroes have this as a tradition.
- In The DCU, during Rogues Revenge, Zoom freed Inertia to train him into torturing superheroes on the grounds that it would make them better heroes. At the end of the series, Inertia murders the Weather Wizard's child and calls himself Kid Zoom. Zoom objects because that would not improve them. Inertia says he just wants to hurt them and reverts Zoom back to the cripple without superspeed. (The Rogues then kill him.)
- Inverted in Necrophim - everybody thinks Uriel is trying to usurp the throne of Hell, but he just wants to loyally serve Lucifer.
- Star Wars: The Sith embody this trope to a point where it has become one of the fundamental aspects of their order. When an apprentice has reached the end of his training, he has to kill his master. If the master dies, he was no longer able to be a Sith master. If the apprentice dies in the attempt, he was not worthy to become a master. If the apprentice doesn't try, he's unworthy of being an apprentice, and is removed to make room for a new one.
- Used in High School Musical 3. Sharpey gets an assistant who literally becomes her understudy in the play. Near the end she tries to take advantage of one of Sharpey's failed plans:
Sharpey Evans: But... you were so loyal. And sweet.
Tiara Gold: That's called acting. You should try it sometime.
- Vaako from The Chronicles of Riddick fits this trope. He is the Lord Marshal's second-in-command, but thanks in part to his wife's promptings, takes his opportunity to betray him in his final fight with Riddick, for the good of the Necromonger faith.
- Repo! The Genetic Opera subverts this with the Largo siblings—Rotti would like them to be ruthless, manipulative, and cunning enough to take over his empire, but they just don't cut it. Later Amber, against all expectations, convinces her brothers to back her as she takes control of Gene Co, but only because the chosen heir, Shilo, turned it down. Shilo would have had to kill her father to inherit the position, but she refused to.
- The Mechanic. Charles Bronson plays the assassin for the mob, who grooms Jan-Michael Vincent's character (Steve McKenna, son of a dead mob boss) as his backup. Eventually, Steve decides he'd rather take over the main job. It doesn't end well.
- Jigsaw from the Saw movies has passed on the secrets of his lethal Games to at least two such Understudies, Amanda and Detective Hoffman. Subverted in that neither of Jigsaw's apprentices actually share his make-your-choice philosophy: The first can't stand to leave any survivors to cope with their trauma after her Games, while the second just likes torturing people.
- And then, in the last twist of the series, Jigsaw is shown to have had a third apprentice, Dr. Gordon, who was loyal to his philosophy and is carrying it out "properly".
- In the Dune books, Feyd-Rautha Harkonen serves as the Bastard Understudy to Baron Harkonen. Feyd-Rautha actually launches at least one assassination-attempt against his uncle, but fails primarily due to bad luck. Notable in that he never really gets around to usurping the throne - the Baron dies by the Gom Jabbar before he gets the chance.
- And Feyd dies in a duel against Paul soon after anyway.
- Also notable is that Feyd is punished by the Baron as a result of the attempt on his life. Not for trying to kill him, mind you, but for FAILING.
- In Stardust, the seven princes of Stormhold are always killing each other to strengthen their claim on the crown. Septimus is clearly the champion at this, and the reigning Magnificent Bastard of the book/film. So it should come as no surprise that Tertius, his much older brother, makes an attempt on his life. And fails, miserably. While Primus, the oldest and wisest, spends most of his time avoiding Septimus.
- L.A. Confidential: Bud White becomes an enforcer for Magnificent Bastard Dudley Smith, learns a few tricks on the way then turns on his mentor.
- Lensman. Among Boskone (and their controllers, e.g. the Eddorians) it is regarded as quite acceptable, even praiseworthy, for an underling to scheme to supplant their superior—the idea being that if he's successful the superior is no longer fit (e.g. not cunning and ruthless enough) to hold their position anyway.
- In C. S. Goto's Warhammer 40,000 Blood Ravens trilogy Dawn of War, Ahriman reflects on Magnus outdid the "False Emperor" and how he outdid Magnus—and how he keeps his own Prodigal Sons down, so no one would supplant him. (For instance, there is no Book of Ahriman, as there as a Book of Magnus, because he stole it.)
- In The Voyage of the Jerle Shannara The Isle Witch is Bastard Understudy to her former Evil Mentor, and current partner in crime The Morgawr. They're both very aware of it, and it pretty much defines their interactions with one another, the Witch always seeking to gain more authority in their relationship, while The Morgawr asserts every last ounce of control that he can over her due to his senior position. Interestingly, she never manages to replace him instead pulling a Heel Face Turn. Then again, she was never even remotely as evil as him.
- Sansa Stark's time with Petyr Baelish has her taking on this role. After being rescued from Cercei Lannister and whisked away from King's Landing, she spends the next few months at the Eyrie, posing as Littlefinger's illegitimate daughter. She spends half her time entertaining Littlefinger's guests and agents, along with babysitting seven-year-old Robert Arryn, whose status as Lord of the Eyrie gives Baelish, as his stepfather, titular rule of the region. The other half, she spends learning from Littlefinger in what could only be described as Magnificent Bastardry 101, as he walks her through his plans to not only take over the Eyrie and the Riverlands (which were given to him by Cercei earlier), but to reclaim the North in Sansa's name (as with all her brothers dead or missing, she is the heir of the Stark family) through a complicated arranged marriage, which would make him the lord of about 60% of Westero's landmass. She might have problems with some of the messier aspects of the plan, but considering where she was before, she's coming along nicely.
- Duke Vessegno to Astfgl, the Satan-figure in Eric. When Rincewind sees them together his first thought, referencing Astfgl's similarity to a Panto Demon King, is "Look out, he's behind you."
- Believe it or not, Big Bad Astronema from Power Rangers in Space fits this. The Psycho Rangers were designed more to drain energy from Dark Specter than to destroy the rangers themselves, thus letting Astronema take over as Queen of Evil. Several scenes from this mini-arc consist of Dark Specter imploring loyal Astronema to find the traitor draining his power, never realizing that she's looking him right in the eyes and lying to his face.... And all of this was after he went to the trouble of luring her back to his headquarters and using cybernetic implants to brainwash away her Heel Face Turn!
- Apparently taking away her ability to feel positive emotions didn't make her more reliable. Go figure.
- At first, almost completely averted, then played straight with a twist in American Gothic: Sergeant Ben Healy is certainly not being groomed to be Sheriff Buck's replacement—instead he lives constantly on the edge as his conscience (in the form of Merlyn) is at war with his cowardice and his loyalty to Buck, whose only Xanatos Gambit consists of constantly balancing the two sides of Ben so that the cop won't reveal what he knows about Merlyn's death. Meanwhile, Buck actually is grooming a successor...his son, Caleb, who does indeed turn on him in the end.
- In the Doctor Who story, The Caves of Androzani, the Corrupt Corporate Executive's secretary deposes her boss, taking over his businesses.
- And exactly the same thing happens in "Dalek".
- Richard Smith-Jones to Holly Day in Slings and Arrows. Although he didn't so much usurp her as tell her to piss off, after his Heel Face Turn. It didn't stick.
- Actor Masato Uchiyama has played two such characters in the Kamen Rider franchise: Yoshio Kobayashi/the Rabbit Orphnoch in Faiz and Shun Kageyama/Kamen Rider Punch Hopper in Kabuto.
- Jamie from The Thick of It is Malcolm Tucker's Bastard Understudy. Malcolm has made Jamie his unofficial second-in-command, and utilises his Violent Glaswegian tendencies whenever he needs some extra help bullying government ministers. Malcolm seems to have chosen his understudy very carefully: while he appreciates Jamie's usefulness, he is also aware that Jamie lacks the charm and intelligence to ever pose a threat to his job. When Jamie eventually attempts a Starscream manoeuvre Malcolm never feels threatened because he knows it will fail.
- Jamie's intelligence is not being given enough credit. He gets things done, he can see when something is a problem and figure out a way to resolve it, and he keeps underlings on their toes. Besides, this troper can't imagine Malcolm suffering idiots under him! Also, Malcolm knows that Jamie's personality—an even more hair-trigger temper unmitigated by an ability or inclination to charm—is enough to keep him from truly becoming a threat.
- In season 2 of Buffy the Vampire Slayer, Spike is basically stuck pretending to be a loyal mercenary to the prophesised leader of vampiredom until, after all of one episode he gets bored and burns the kid into ash.
- Then has to spend the second half of the season playing the role again to Angelus (this time while waiting to heal and then pretending to still be crippled until he found his moment to strike).
- Smallville: In Season 10's "Luthor" Clark visits an Alternate Universe in which he, Tess, and Lex all played this role to Lionel Luthor. Lionel plays the three of them against each other, hoping that the constant competition, and his belittlement of them will eventually drive one of them to kill him, ensuring that he and LuthorCorp (which is very close to being The Empire in this world) will have a worthy heir. None of them can quite pull it off though. Following his escape into Earth-1, the search for a new Understudy becomes a defining part of Earth-2 Lionel's character, and he makes repeated attempts to draft Lex's clone, Alexander, into fulfilling this role. That having failed, he may be cutting a deal with Darkseid in order to get the original Lex back.
- The Shadow Line is full of them. Ratallack to Bob Harris, Jay Wratten to his uncle Harvey (and later Joseph Bede) and Patterson to Commander Khokar -- all of whom eventually supplant their superiors and join Gatehouse in his new Counterpoint. And even Gatehouse himself is implied to have been working to undermine the Counterpoint leaders even before they tried to kill him.
- In C-drama The Holy Pearl, a loose adaptation of Inuyasha, Hu Ji (Kagura-Expy) is this to Naraku/Ghost King. She resents being subordinate to him and spends a considerable part of the series trying to arrange his demise. And eventually almost succeeds.
- In The Lion In Winter, Henry II deliberately encourages conflict amongst his sons to toughen them up for their role as leaders. He specifically grooms his inept, youngest son John to take over as his successor (and has a Heroic BSOD when he discovers the boy scheming to usurp him with one of his other sons and the King of France.)
- Perhaps taken quite literally, Puckeridge in Tom Stoppard's play The Real Inspector Hound fits this trope, as well as that of Magnificent Bastard. He's established to be the subordinate theatre critic to both Higgs and Moon, the latter of whom is reviewing a bastard child of The Mousetrap because Higgs is missing. Eventually, Puckeridge manipulates events so that Higgs is the (really) dead body on stage, and both Moon and rival critic from another paper, Birdboot, are both dead.
- Video Game Example: X-Men Legends II: Rise of the Apocalypse casts Mr. Sinister in this role to that game's Big Bad, Apocalypse. With predictable results.
- Samir Duran is Kerrigans understudy in StarCraft. Not quite as magnificent as Kerrigan, but close.
- Or so he seems...
- Advance Wars 2: Black Hole Rising Hawke ends up killing Sturm at the end of Campaign.
- Oh dear. Vanitas to Master Xehanort in Kingdom Hearts: Birth By Sleep.
- Let's not forget Ansem's betrayal by Xehanort and the original persons of Xigbar, Xaldin, Vexen, Lexaeus, and Zexion
- Doubly so in the case of Braig/Xigbar. Out of all the Apprentices, he and Xehanort were the only ones who were bad people before they succumbed to darkness.
- Also, Riku to Maleficent to a certain degree.
- Let's not forget Ansem's betrayal by Xehanort and the original persons of Xigbar, Xaldin, Vexen, Lexaeus, and Zexion
- Fawful shows shades of this in his final scenes in Mario & Luigi: Superstar Saga. Sure enough, by the time of Bowser's Inside Story, he's a full-blown Dragon Ascendant.
- The Final Fantasy series is fond of this trope. Kefka and Kuja both betrayed the evil masters who originally gave them their powers to become the game's true Big Bad.
- Happens a few times in Survivor Fan Characters: in Season 3, Baxter took Hope under his wing and taught her the joy of backstabbing her closest friends; in Season 5, Jessica taught Marius the ropes of Survivor, and after the merge, he organised her blindside, and eventually won the game; also happened in Season 6 with Vinnie and Sin, but this didn't go as far as the previous examples.
- Starscream in Transformers wishes he could get away with this and tries many times to no avail, as he is not the Bastard Understudy but the Trope Namer for The Starscream. He almost gets away with becoming this trope in Transformers Prime when Megatron seemingly died.. unfortunately for Starscream, he turned out to merely be in a coma.
- In the Beast Wars episode "Possession", Blackarachnia betrays Megatron for Starscream (yeah, that Starscream), convinces him to take her under his wing, and then double-crosses him for Megatron at the end of the episode. Starscream can't catch a break.
- She was also a Bastard Understudy to Tarantulas.
- The Galaxy Force AKA Cybertron version of Starscream IS this however. And he succeeded in double-crossing Megatron until the writers brought him back.
- She was also a Bastard Understudy to Tarantulas.
- Snively in Sonic Sat AM. Inverted somewhat since while Robotnik is perfectly convinced he is under his thumb, he does not view Snively with much high regard outside a toady and a punching bag. Snively merely picked an opportune time Robotnik had (supposedly) desposed of himself (with Word of God stating his rule would not have lasted long before the new Big Bad entered the fray). This is played with in the Archie comics where Snively has made numerous short lived attempts to overthrow Robotnik, to the point the latter just considers it a fun little game of "roulette".
- Gargoyles: Thailog was this to Xanatos, but by the time he makes his first onscreen appearance, he's already decided that he's learned all he can and is ready to strike out on his own as a villain in his own right. He does nearly kill Xanatos, Goliath, Elisa, and Sevarius as a parting gift.
- Princess Azula from Avatar: The Last Airbender seems to have been this to her father, but ultimately with a couple of twists- first, that she's already smarter than he is (or at least more willing to use smarts instead of force) by her first appearance, and second in that the finale proves her to be genuinely loyal to him. Thus many Fan Theories of her being The Starscream/ Dragon Ascendant were Jossed.
- Slade of Teen Titans actually wants one of these (yes, including the betrayal part, as his dialogue with Robin makes clear when he complements him on threatening him- it'd keep him sharp if nothing else). So far, however, he's had phenomenally bad luck in keeping one, and even lampshades this at one point.
- Brother Blood, who ran an entire school for apprentice supervillains, lampshades his own failure with this trope, when both his newest student and his star-pupil turn out to be undercover good guys rather than neophyte Bastard Understudies:
Blood: Was anyone at my school actually there to learn?
- On Jimmy Two-Shoes, every member of the Heinous family is this, being groomed to overthrow and freeze their fathers. In one episode, Beezy temporarly becomes this thanks to Screw Learning, I Have Phlebotinum.
- In Transformers Prime, the newest Starscream blurs the line between this and being, well, himself.
- An episode of Evil Con Carne has General Skarr with a robot version of himself, who helps him usurp command from Hector. But by the end of the episode, the robot Skarr takes his advice of "Stabbing in the back and twist! Twist! TWIIIIST!" to heart, and manages to take command from him with a robot army. Skarr is very proud and happy of this... and then he's blasted by all the robots.
- Ernst Rohm and Heinrich Himmler served Hitler faithfully, but Hitler never had any illusions what they would do if they had the chance. When the Third Reich folded, Himmler attempted to surrender to the Allies. Rohm was already dead, on Hitler's orders.
- Actually, Hitler trusted Himmler above nearly all of his other subordinates, even calling him "der treue Heinrich" (the loyal Heinrich). Himmler's betrayal was probably what pushed him over the edge - it certainly resulted in an epic Villainous Breakdown, according to those who were there. Der Untergang expertly reconstructed it.