Big Bad Duumvirate



"Well, I guess we're gonna be friends after all."

- Clarence Boddicker to Dick Jones, Robo Cop

What's worse than one Big Bad? Two Big Bads, possibly more, working in intentional collusion with each other. Sometimes they will work together just fine; being all respectful and well, but more often than not there will be rivalries between them, and they will tend to break out into a literal example of an Enemy Civil War.

Not to be confused with The Dragon (a main villain clearly subordinate to the Big Bad), though if one of them becomes dominant he may reduce the other(s) to the position of Dragon With an Agenda, Dragon in Chief and/or The Starscream. May overlap with Unholy Matrimony. Contrast Big Bad Ensemble, where there are also several Big Bads operating simultaneously, but not neccesarily working together or even interacting in any way.

See also Villain Team Up. Contrast Co Dragons, where one Big Bad is directly served by two or more equally ranked lieutenants.

No Real Life Examples Please

Anime & Manga

 * The God Hand from Berserk
 * Yami Bakura and Marik Ishtar in the Battle City arc of Yu-Gi-Oh until
 * Placido, Jose and Luciano in 5D's
 * Kotomine and Gilgamesh in Fate Stay Night. Kotomine makes the plans, Gilgamesh calls people mongrels and swordspams them to death. Or doesn't. He helps if he feels like it, anyway.
 * Sailor Moon: Several incarnations of the true Big Bad, Chaos is the true main villain for the Story Arc, while the person we believe is Big Bad is The Dragon. However, a few have been to equal Big Bad levels, namely Queen Beryl and Queen Metallia of the first story arc.
 * V. V. and Charles of Code Geass.
 * Towards the end of Zeta Gundam Paptimus Scirocco and Haman Kahn join forces. They trash the hell out of Char doing it, too.
 * The Innovades and A-Laws from Gundam 00.
 * In Naruto, Tobi forms an alliance with Kabuto Yakushi.
 * It's debatable whether Tobi and Pain's relationship from earlier in the story was an example of this with Tobi being dominant or simply a straight-up single Big Bad and his Dragon in Chief. Tobi is the master planner behind the scenes while Pain is the unquestioned leader of Akatsuki with enough power to flatten most armies. Each has their own diabolical plan that actually conflicts with the other, and it's never revealed if either one knew what the other was planning.
 * In the most recent arc in the Bleach manga, Shukuro Tsukishima shares this with
 * The third Bleach movie, Fade to Black, has this split between Homura and Shizuku, two siblings that The Lancer adopted before becoming a Shinigami. This pair actually provides a pretty interesting variation: It's clear that these two are the ones responsible for starting and intensifying the conflict within the third film, but Shizuku is much more action-oriented than his elder sister, being the one to wield that memory-erasing Sinister Scythe, while Homura, with her Mass Teleportation, acts as backup support. Furthermore, while Homura is paranoid, stubborn and near-obsessive, Shizuku is a lot calmer, rational and emotionally stable, but of the two, she's the one calling the shots and directing their actions, while he's loyal and obedient to the letter, even when he disagrees with what she says.
 * In Soul Eater during the Book of eibon Article Noah was the Main Villain until it was revealed to be The Book's intelligence the Tables of Contents who wanted to teach the world of Asura's madness and also creates a new Noah representing Wraith to replace The Noah of Greed.
 * The Fishman Island Arc of One Piece has.
 * Eyeshield Twenty One's last arc has a de facto Big Bad Duumvirate on the American Pentagram. Elitist goliath Mr. Don is the team captain and the undisputed leader of the team, yet despite his Genius Bruiser status, he spends most of his time serving as the centre, which leaves his ability to lead the team somewhat handicapped. As such Evil Genius Clifford D. Louis makes and executes most of the plans; he's also the only player who isn't frightened of Mr. Don and whom the latter doesn't try to order around, making them an example of this trope.
 * In Gao Gai Gar FINAL Palparepa is officially considered the leader of Eleven Masters of Sol and Pauls Abel is considered to be his Dragon, but in reality they have divided the Big Bad duties between each other and Abel clearly acts like Palparepa's equal.
 * The Table of Contents and Noah in Soul Eater because the Index was the true mastermind behind Noah.

Comics

 * Alexander Luthor and Superboy-Prime in Infinite Crisis.
 * Solaris and Vandal Savage in DC One Million.
 * The three lords of hell in The Sandman and Hellblazer: Lucifer Morningstar, Azazel and Beelzebub. Somewhat subverted in that Lucifer is by far the most influential to storylines and Azazel is taken care off in The Sandman. Beelzebub has had little to no importance.
 * also swerve back and forth with this, given that they only tenuously qualify as separate beings anyway and
 * The Leader and MODOK in Fall of the Hulks.
 * Hank Henshaw and Mongul in The Death of Superman.
 * Although by mid story it was fairly clear that Mongul was the underdog of the two.
 * The Bulats and Vera from The Punisher MAX Volume 5: The Slavers, the leaders of an eastern european human trafficking ring. Cristu Bulat and Vera get along well because they are both heartless business men, while Tiberiu, Cristu's father, is starting to annoy them and damage their business with his unnecessary cruelty and craziness. All of them barely qualify as human beings.
 * The Sin City story Hell And Back has the corrupt police chief and assassin guild leader working side-by-side along with
 * Mr. Sinister and Apocalypse fill this role for a good portion of the X Men comics, though Sinister is also clearly identified as The Starscream.
 * Megatron and Galvatron in the UK Transformers comic story Time Wars is an example of the big bad teaming up with his past/future self. Predictably a lot of other characters don't survive the story.
 * A lot of story arcs in Les Légendaires involve two Big Bad working together, usually an actual villain and an Anti Villain. Unsurprisingly, it often ends up with the actual Big Bad betraying his comrad and the Anti Villain helping the heroes:
 * In Book 3 and 4, Anti Villain General Rasga teamed up with Darkhell. Darkhell eventually betrayed him, and Rasga sided with the good guys for the end of the battle.
 * later, Book 5 and 6 involved Pirate Captain Ceyderom teaming up with . Ceyderom later betrays by siding instead with past Darkhell (or at least trying; it seemed like Darkhell was merely tolerating his presence), and  redeemed himself by committing a Heroic Sacrifice;
 * The Anathos Cycle starts with Hero turned Anti-Villain Elysio being forced to team up with Darkhell under the Guardian's orders.

Fan Fics

 * Princess Jody and the Dark Overlord from Super Milestone Wars
 * In Disney fanfic The Hellbound Hearts, it's essentially a team-up of numerous Big Bads from previous Disney films all either teamed up or fighting against one another. Still, due to the fact that each one has their own agenda, it's hard to figure out which character will end up being the main antagonist. That being said, this trope is played straight with Xanatos and Maleficent, with both under the belief they're in charge of their particular faction.
 * In the Death Note fic Low Light L and Kira after L (under the influence of the Death Note and Love Makes You Evil) pulls a Face Heel Turn and joins forces with Kira.
 * The Dresden Files / My Little Pony Friendship Is Magic crossover fic My Little Denarians brings us a Big Bad Duumvirate of Nicodemus and Discord.

Films

 * It is common in trilogy's or series is to have the second movie feature not only the main big bad of the series, but also a smaller villain to raise the stakes.
 * As the main quote in this page suggests, Clarence Boddicker and Dick Jones from Robo Cop
 * Can be found in the Scream series..
 * The James Bond film series is fond of this trope:
 * Kamal Khan and General Orlov in Octopussy
 * General Georgi Koskov and "General" Brad Whitaker in The Living Daylights.
 * General Arkady Grigorovich Ourumov and Janus in Goldeneye.
 * Ouromov devolves into a plain minion pretty early on, if he was ever anything else. Janus is clearly the man in control.
 * It is hotly disputed whether Elektra King and Renard's relationship is an example of this, Renard being The Dragon or King being Renard's puppet.
 * Dominic Greene and General Medrano in Quantum of Solace. In addition, a Big Bad quinumvirate appears, in the form of Guy Haines, Gregor Karikoff, Moishe Sharoff and Dominic Greene, at the opera house in Lake Constance, Austria. There are probably even more members; that's just the ones Bond caught on camera.
 * Medrano is a puppet. He thinks he is in this trope, up until the part where Greene makes it clear if he refuses Quantum's terms he'll be killed and replaced by the next wannabe dictator (clever camera shooting perhaps implying this might be Medrano's own bodyguard).
 * William Stranix and in Under Siege.
 * and in The Bourne Supremacy.
 * Miraz, Glozelle, and Sopespian have elements of this in the film of Prince Caspian- Miraz is dominant, but he is forced to (grudgingly) rely on the other two.  The three have elements of this dynamic in the book as well, though the movie gives all three more screen time and therefore emphasizes it more.
 * Cyrus "The Virus" Grissum and Nathan "Diamond Dog" Jones in Con Air.
 * Arguably, Miles Quaritch and Parker Selfridge from Avatar. "Arguably" because, by the end of the film, Enemy to All Living Things Quaritch has rendered the saner Selfridge entirely impotent.
 * Eddie Arkadian and Sho'nuff the Shogun of Harlem in The Last Dragon.
 * Torrez, Senator Mc Laughlin, and Von Jackson in Machete.
 * The Riddler and Two Face in Batman Forever with one proving the brawn and the other the brain.
 * It appears to be an unwritten law of comic book movies that a sequel must contain at least two canon villains. Penguin and Catwoman; Joker and Two-Face; Venom and Sandman; Justin Hammer and Ivan Vanko etc.
 * It is unclear if Darren "Wall Street" Bettencourt was The Dragon to Mr. Kwai in the first of The Transporter movies, or if it was an example of this, with Kwai as the more senior partner.
 * Megatron and in Transformers Dark of the Moon.
 * Though by the end of the move, it's clear that  is the one calling the shots; as Carly points out, Megatron is basically " 's bitch."
 * It's heavily implied that the crime syndicate in Drive is ran jointly by Bernie and Nino, though both aren't always aware of the other's actions.

Literature

 * Duumvirate. It's right there in the title!
 * Subverted in The Lord of the Rings. Saruman sees himself as Sauron's ally and has full plans of double-crossing him once he gets his hands on the Ring- but Sauron is both far more powerful and more intelligent, knows full well about Saruman's plans, and considers him varyingly a useful tool and a nuisance, but never an equal of any kind.
 * Played more or less straight with Morgoth and Ungoliant in The Silmarillion: they team up to destroy the gold and silver trees, humiliating the Valar and setting off the War of the Silmarils, but it ends poorly when Morgoth tries to double-cross Ungoliant. Weakened by pouring his power into making his army and Ungoliant empowered by the light of the Two Trees, only a posse of Balrogs saves him from being devoured.
 * Grand Admiral Thrawn and the insane Jedi Master Joruus C'baoth from The Thrawn Trilogy count as this - they have a mutually beneficial alliance, but each has schemes separate from the other and plans to dispose of the other after he's served his purpose. At the trilogy's climax, they are faced simultaneously by two different sets of heroes.
 * In the Hand of Thrawn Duology, three people are working to create and maintain the illusion that Thrawn has returned, but of the three, Disra and Tierce are the ones at odds. Flim mostly serves as The Watson, and doesn't seem to have much ambition of his own beyond surviving and being handsomely rewarded.
 * While not exactly a Big Bad herself, Admiral Cha Niathal works with Jacen Solo in Legacy of the Force
 * Opal Koboi and Briar Cudgeon in Artemis Fowl: The Arctic Incident.
 * In the Warhammer 40000 series Ravenor, the third book features a union of the two big villains, Zygmut Molotch and Orfeo Culzean. Either could qualify as a Magnificent Bastard, and the books hint on the friction that can develop when two MBs try to work together for extended periods.
 * Probably the best way to sum up the... odd relationship main villains Kiva and Akhlaur have in the Forgotten Realms Counselors and Kings trilogy. They hate each other (or at least, Kiva hates Akhlaur personally- he holds her in contempt, but that's how he treats everyone) but work together to advance their own goals- power (for Akhlaur) and vengeance (for Kiva). As he treats her like a servant, it probably would count more as Dragon With an Agenda except that Kiva herself in no way sees herself as subordinate and has tons of plans apart from Akhlaur, and in fact tries her hardest to manipulate him (though its made clear he knows what she's doing, and is playing along for his own entertainment). They're best summed up as two distinct Big Bads who for the moment happen to be going in the same direction.
 * Lampshaded in the children's book "Star Wars ABC's," where most of the major characters get an alphabetic poem written about them. In "Z is for Zuckuss," we read: "Uh-oh, here's that bad quartet/Of bounty hunters Boba Fett/Zuckuss, Bossk and '88...."
 * The War of the Flowers by Tad Williams deconstructs this- it starts out with a triumvirate of main villains (fairy lords Hellebore, Thornapple and Foxglove), with Hellebore dominant because he's the one with brains, but the other two still clearly his equals, rather than underlings. Then Foxglove gets cold feet and is demoted to hanger-on, while Thornapple is still close to Hellebore's equal and perhaps the closest thing he has to a friend. By the end, Foxglove is a complete nonentity and Thornapple is a clear minion, if an important one- Hellebore is now calling all the shots.
 * Happens between Belasco and Dahun in the Demonwar Saga, most recent subseries of The Riftwar Cycle. Each has his own goals and is manipulating the other to accomplish them..
 * Happens several different times in the Redwall series, although one Big Bad is usually obviously the stronger one and the other doesn't live long. Tsarmina briefly formed one with Bane in Mossflower, Swartt Sixclaw formed one with Zigu in Outcast of Redwall, and for most of Martin the Warrior, Badrang and Clogg formed one.
 * The Ilse Witch and her former mentor The Morgawr form one in The Voyage of the Jerle Shannara. They have an interesting dynamic, as she's his former Dragon, pupil, and Bastard Understudy, which causes him to treat her as the junior partner, something she deeply resents. When the inevitable breakdown occurs and they do go head to head, the results aren't very pretty.
 * The necromancers Cowl, Grevane and Corpsetaker in Dead Beat, the seventh book of The Dresden Files. Though while they're all technically working together to find the Word of Kemmler, they all intend to betray the others and take the Word's power for themselves.
 * A very tense one shows up in The Warlord of Mars, the third book in the John Carter of Mars series, consisting of Matai Shang (Priest King of the white Martians, or Therns) and Thurid (a warlord of the black Martians, or First Born). Later in the book it becomes a triumvirate when Salensus Oll (Evil Overlord of the yellow Martians, or Okar) joins up. Since these three have their own goals and ambitions and are united only by their hatred of the eponymous hero, there's a fair bit of backstabbing all around.
 * For most of the Tales of Kolmar trilogy the baddies are Marik of Gundar and Berys. Berys believes Marik's The Dragon, and he is the more powerful one, but Marik's more important than that and knows it. Ultimately Berys summons the ; the result is under his control but only barely.

Live Action TV

 * 24 has done this a few times:
 * Andre and Alexis Drazen in Day 1,
 * The German arms dealer Max, Alexander Trepkos and several other oilmen in Day 2, being the collective men behind Peter Kingsley.
 * Ramon Salazar and his brother Hector Salazar in Day 3.
 * Debatably,
 * Abu Fayed and Dimitri Gredenko in Day 6; later replaced by . The former become a triumvirate if General Mohmar Habib is counted.
 * Jonas Hodges and General Benjamin Juma in Redemption and Day 7.
 * Briefly, and Sergei Bazhaev near the beginning of season 8.
 * In Battlestar Galactica, It ends badly.
 * When Angel initially did his Face Heel Turn in Buffy the Vampire Slayer, there was more or less an equal partnership going on between him, Spike, and Drusilla. But, as Drusilla became more and more enamored with him, and Angel constantly belittled Spike for his crippled status, it became pretty clear who the alpha dog was.
 * Speaking of Angel, and the Beast in Season 4.
 * Except both were subservient (reluctantly, in the case of ) to Jasmine.
 * In Hercules: The Legendary Journeys, several Olympian gods were dedicated to destroying Hercules. They normally worked alone, but at times, they teamed-up. In "Reunions," for example, Hera takes over Olympus with Apollo and Ares siding with her.
 * The Shadow Line has, the leaders of Counterpoint.
 * Star Trek Deep Space Nine: During the Dominion War arc, Gul Dukat and Weyoun serve as commanders of the two halves of the Dominion fleet, and despise one another. Dukat is later replaced with his Dragon, Damar,.
 * Nikita: The Bigger Bad Oversight is composed of a committee, whose members appear to be equal (though Madeleine gets the most screentime, so she's arguably the leader).
 * Subverted in Dark Oracle where the apparent Big Bad Duumvirate of Blaze and Violet are revealed to be Co Dragons to the real Big Bad, The Puppet-Master.
 * The series 4 finale of Doctor Who featured Davros and the red Supreme Dalek leading the Dalek forces in the attack on Earth.
 * Subverted in Dark Oracle where the apparent Big Bad Duumvirate of Blaze and Violet are revealed to be Co Dragons to the real Big Bad, The Puppet-Master.
 * The series 4 finale of Doctor Who featured Davros and the red Supreme Dalek leading the Dalek forces in the attack on Earth.

Video Games

 * Bowser and Ganondorf have this sort of relationship in The Subspace Emissary. As one may expect, Ganondorf gets a little tired of Bowser's company. It becomes a triumvirate if Wario is included, though he rarely bothers to involve himself with his fellow "teammates".
 * Ganondorf's pretty clearly the one calling the shots. It's more like Wario and Bowser are Co Dragons to Ganondorf.
 * Technically, all three villains end up being dragons to Master Hand, who is in turn a literal puppet of Tabuu.
 * Maleficent and Ansem in the original Kingdom Hearts.
 * Not really. Most of the game, Maleficent seems to be doing her own thing. In fact, she's more or less the Big Bad throughout most of the game with other disney villains being her subordinates. (Maybe that makes them dragons?) The only time Maleficent and Ansem work together is during Hollow Bastian but even then it seemed Ansem was more like The Man Behind the Man, abit for a short time.
 * Actually played with a lot in Kingdom Hearts. At first it looks like the leader of The Heartless in the first game is the Big Bad. The Second game introduces Xemnas, leader of a species called the Nobodies, but it's revealed they're 2 fractured halves of the same person and work for the same goal. Subverted again when it's revealed that there's a Man Behind the Man... as himself. So 4 "different" people are the same big bad.
 * Tekken
 * Heihachi Mishima and Ogre in 3.
 * Kazuya Mishima, Jin Kazama and in 6.
 * Grand Theft Auto.
 * Frank Tenpenny and in Grand Theft Auto San Andreas.
 * Jerry Martinez and The Mendez Brothers in Grand Theft Auto Vice City Stories.
 * A Big Bad triumvirate is found in Oddworld: Abe's Exoddus. General Dripik of the Slig Barracks, Vice President Aslik of FeeCo Depot and Director Phleg of Necrum Mines and Bonewerkz, respectively. An inversion of The Man Behind the Man occurs, as the previous game's Big Bad, Molluck, is revealed to have been their superior.
 * Gol and Maia Acheron of Jak and Daxter.
 * Shang Tsung and Quan Chi in Mortal Kombat Deadly Alliance.
 * Kombayn Nikoladze and  Chinese General Kong Feirong of the first Splinter Cell game. Like the Bourne Supremacy example,
 * Wild Arms 1 has one of the most Nightmare Fuel inducing examples in the second half.
 * The eponymous characters in Star Wars: Knights of the Old Republic II: The Sith Lords are often called the Sith Triumvirate, although only Darth Sion and Nihulus ever work together as equals; the first third member was the Big Bad and Sion and Nihilus were her Co Dragons and the replacement third member was never an official member of their organization. Cut content shows that Sion and Nihilus' relationship is actually a subversion, as during a deleted scene from the game that was eventually restored by modders, Darth Sion confronts Darth Nihilus aboard the latter's ship to boast about his success in "killing" the player character. Nihilus responds by forcing Sion to the ground effortlessly, and then letting him walk away humiliated; Nihilus didn't care about Sion, to the point where he considered the Lord of Pain so weak that he wasn't worth killing.
 * Pretty much every Fire Emblem game in the Akaneia canon features Medeus and Gharnef in such a duumvirate - Gharnef specifically revives Medeus from his centuries-long death for this purpose, but it's implied he has plans which transcend Medeus and will (try to) dispose of him once he's done; for his part, since he cannot leave his castle without losing his power or risking death, Medeus pretty much relies on Gharnef to actually execute their plans for dominating Akaneia.
 * in Ratchet and Clank Future: Quest for Booty.
 * in Xenogears.
 * Final Fantasy XI had the Ace Cardians in the Windurst mission line.
 * Final Fantasy XII had
 * Final Fantasy XIII has
 * Actually a unique example because
 * In Psychonauts, Dr. Loboto and work together to conquer the world. The latter eventually  though, after Loboto falls out of the asylum.
 * Diablo, Mephisto and Baal, the Three Prime Evils in the Diablo games. Diablo is the Big Bad in the first game and at least the Final Boss in the second, and Baal is the Big Bad in the expansion, while Mephisto is an intermediate boss in Diablo II, but for the plot as a whole (if anyone notices it) they are equals. They seem to be loyal to each other too (well, they are brothers).
 * 'War Craft: In the first game, Gul'dan and Medivh are this, both being responsible for the orc invasion. Also, ever since Sargeras only mostly kicked the bucket, his Co Dragons Archimonde and Kil'Jaeden have been carrying on his crusade against life together. Until Archimonde bites it, that is, leaving Kil'Jaeden sole acting Big Bad.
 * Blaz Blue features, two Complete Monsters who have been orchestrating just about every bad thing that's happened in the series' storyline from behind the scenes, for well over a hundred years, all in their mission to, essentially, kill God. Making matters worse is that both of them are insanely brilliant, one being an amoral Mad Scientist (though a very calm and cultured one), the other being a psychopathic tactician who delights in taunting people and ruining lives. Oddly enough, the two get along rather well with each other, and act as Red Oni Blue Oni to one another.
 * Earthbound: Considering what game we're talking about it's very open to interpretation, but Giygas and Porky Minch as this is a common interpretation; Giygas himself is pretty much incapable of coherent thought by this point so Porky pulls his strings, but at the same time Porky is not even close to being powerful (or bothered) enough to do this stuff himself.
 * The teamup of Doctor Doom and Albert Wesker in Marvel vs. Capcom 3. There's also a Sealed Evil in A Can that they accidentally released to count,
 * DC Universe Online has Lex Luthor, The Joker and Circe as the trio who are in control of the villain side.
 * In the Zelda Oracle games,
 * Fall From Heaven reverses the usual fantasy conventions: The good gods are individually powerful but tend not to get along well, while the evil ones are all trying to twist Creation together just to make a point to the original Creator. They even run their afterlives (hells) together as a well-oiled machine to create twisted daemons, unlike the good gods whose afterlives are all disconnected.
 * Kerrigan and Mengsk become this briefly in Broodwar, untill Kerrigan decides othervise. In somewhat of a subversion, they are working with the good guys against a faction of space nazis. By the time they return to being villains, they're at each other's throats again.
 * in LA Noire.
 * TK and  in Dead Rising 2.
 * In Sonic Generations,
 * In Saya no Uta, this overlaps with

Webcomics

 * The Three Fiends, aka the Directors, from Order of the Stick form a triumvirate. The three seem to be equal in every respect, which makes sense, since their goal is to bring an end to the fighting between their three races. They also might turn out to be the Big Bads, though they haven't got much screen time yet.
 * Xykon and Redcloak originally were a duumvirate (or triumvirate if you count Right-Eye), but this eventually changed when it became clear as Xykon became more powerful and more completely depraved. Redcloak was eventually demoted to The Dragon (and possible Starscream).
 * Brian and Angelo from Our Little Adventure. In addition to that, they are also a married couple.
 * Magus and Sirleck from El Goonish Shive.

Web Original

 * Whateley Universe example: The Bastard and The Necromancer.
 * Red vs. Blue's eight season, Revelation has.
 * Starship has Pincer and.
 * Coyle Command is run by Coyle Commander and the currently unseen Baroness Crossland. Anni would appear to believe he is a part of it.

Western Animation

 * The Quintessions from Transformers, being many villains that work together and being that each has multiple personalities.
 * During G1's third season, the Autobots had to contend with the Decepticons and the Quintessions (who sometimes worked together to achieve their own mutually exclusive ends).
 * Moog Magister and Hector Sinestro in Monster Allergy.
 * Xanatos and Demona for the first season of Gargoyles and about 1/3 of the second season. At that point their goals and methods become too divergent, and Xanatos teams up with the heroes to stop Demona from turning the population of New York to stone.
 * In Teenage Mutant Ninja Turtles: Fast Forward, the two main villains were invading alien Sh'Okanabo and corrupt C.E.O. Darius Dun. Despite different goals and storylines, they established a resource-sharing relationship, where Darius gave Sh'Okanabo the stolen plans for nephew Cody Jones' time window, in exchange for the assistance of the turtle clones Sh'Okanabo had created.
 * In the 1987 cartoon, the conventional opinion seems to be that Shredder is The Dragon and Krang is the Big Bad, but that could easily be just because The Dragon is a much better-known trope than Big Bad Duumvirate. There is no question that Shredder sees himself as a Big Bad in an equal partershp with Krang, and it usually seems as if most of the characters agree (Krang may be the only one who sees himself as Shredder's boss). And in an alternate history where the villains succeed in taking over the world, who is the natural choice for the position of Emperor? Hint: The episode isn't titled "Krangville."
 * In seasons four through six of The Fairly Odd Parents, Anti-Cosmo, the leader of the anti-fairies, and HP, the leader of the pixies, seemed to have equal claim to the title of Big Bad. This is especially notable in season six, where the two never appeared without the other. With the birth of Poof at the beginning of season seven, we might be seeing the anti-fairies take on full Big Bad duties, but it's too early to tell.
 * In Season Two of Metalocalypse,  In a less blatant example, General Crozier and Cardinal Ravenwood could be considered the first season's Big Bad Duumvirate (with Metal Masked Assassin as their Dragon).
 * The Almighty Tallests of Invader Zim that the Villain Protagonist serves. Normally it'd just be a singular Evil Overlord, but since Red and Purple are the same height they're the joint rulers of The Empire (though Red seems to be a bit more competent).
 * In Disney's Dinosaur, the villains are a pair of Carnotaurus threatening to destroy the Herd and prevent them from returning to the Nesting Grounds.
 * Mojo Jojo, Princess, Fuzzy Lumpkins, and Him teaming up in the Powerpuff Girls parody of the Beatles Meet the Beat-Alls.
 * Ben 10 did it several times in all three series:
 * Big Bads Vilgax and Kevin 11, respectively from season 1 and 2 or the original serie, teamed up at the end of season 2 in an attempt to take the Omnitrix from Ben. Kevin's betrayal eventually caused the alliance to frail and led to both of them being trapped in the Null Void.
 * Later, the Forever King, Big Bad of season 4, assemble a team made of several of Ben's old ennemies for the season finale while most of them weren't that much of Big Bads (guys like Clancy or Rojo had only appeared once before), the team still included Charmcaster (Gwen's Archrival) and Dr Animo (Ben's third most dangerous enemy back then).
 * Vilgax teamed up with Albedo in the Alien Force finale in a new attempt to take the Omnitrix. Though the alliance was successful, Vilgax then betrayed Albedo, and Ben was able to defeat him alone.