Yin-Yang Bomb



"''"Light belongs to shadow, shadow to light

Chasing one another to the very end"''"

- Bonnie Pink, "Ring a Bell" (translated)

The Ideal Hero is the champion of all that is good. Thus, his power will be that of light, he will dress in white or bright primary colors, like blue and red, and he will rarely take proactive action against the villain, preferring to play defensively and protect and defend the innocent. He will also champion the causes of love, courage, and hope. Only natural, such good powers could never be used for evil!

Of course, sometimes you have the Anti-Hero, the guy who wields the power of darkness, powers himself on negative emotions, and probably has an angsty past. He probably dresses in all black, too. In extreme cases, the Dark Hero would like nothing, nothing better than to wrap his hands around his archnemesis' throat and strangle the life out of him. Think Sabata, Raven, and Batman.

But our guy, the Yin-Yang Bomb guy, doesn't care about all those things. He uses both. Not just that, but often, he will combine them into something higher and invariably ridiculously more powerful. Dark and light are not evil and good. They're not even diametrically opposed. To resolve the storyline or beat the boss, the hero must grab the reins of both and wield them in a harmony of fusion.

A variation uses order and chaos instead of light and dark, and another uses Harmony Versus Discipline.

Sometimes a subtrope of All Your Powers Combined. Naturally, good buddies with Dark Is Not Evil, or, in the case that the villain uses this, with Light Is Not Good. The result is frequently Non-Elemental, ignoring elemental resistances. Or, as demonstrated in a few cases, the effect may be able to completely destroy something and recreate it (usually as a child). Sometimes, an Enemy Mine with a villain may result in them combining their powers to do this.

Unrelated to The Tumor, a bomb from Homestuck that looks like a yin-yang symbol. Also unrelated to Reimu Hakurei and her yin-yang orbs that she occasionally uses explosively.

Anime & Manga

 * In the climax of the Record of Lodoss War OAV miniseries, only Parn, wielding both the Holy Sword of Falis and the Demon Sword Soul Crusher, can stop the resurrection of the Mad Goddess Kardis.
 * Gao Gai Gar's "Broken" right hand represents destruction, his "Protect" left hand protection. Individually, they function as a shield, Protect Shade, and his Rocket Punch, Broken Magnum. Combined, they form the Finishing Move Hell and Heaven, which destroys a Zondar while cleanly removing its core. Less directly, in the OVA, TenRyuJin is the combined form of KouRyu and AnRyu (Light Dragon and Dark Dragon), and Big Bad Palparepa matches Hell and Heaven with his own God and Devil, though it's unclear if it really counts except in name.
 * It's worth noting that in GGG, destruction isn't necessarily an "evil" power -- GaoGaiGar's original form, Genesic, is a god of destruction, with the explanation that destruction is necessary for new beginnings, and allows for "the challenge of a new hero."
 * In Super Robot Wars K, El Dora V gains a finishing move which is a visual shoutout to Hell and Heaven. Its name? El Inferno Y Cielo. Regrettably, El Dora Soul does not retain it.
 * Slayers
 * The final Big Bad of Slayers TRY is the fusion of Mazoku Lord Darkstar and its opposing god Volphied. It took the a spell that combined the powers of Ruby Eye Shabranigdo and Flare Dragon Celphied, channeled through the Dark Star weapons, in order to defeat him. The spell had the effect of a complete rebirth, allowing Filia to raise the Big Bad as a child.
 * In Slayers NEXT, the timid white mage Sylphiel mastered the powerful Black Magic spell Dragon Slave just to impress the guy she liked.
 * Digimon Frontier: Light-wielding Koji had to take on Koichi's dark powers to give the team the edge needed against Lucemon, who had learned to combine darkness and light into his ultimate attack.
 * In Bleach, Ichigo (as well as the Vizard and Arrancar) wield both the powers of the Shinigami and that of the monsters they fight, the Hollow.
 * Naruto
 * 4-Tails Naruto's chakra cannon attack is depicted in the anime as a dense concentration of spheres of both red Kyuubi chakra and Naruto's blue chakra.
 * Also, senjutsu, or "Sage Energy", is a fusion of a shinobi's chakra and of the all-present energy of the world around them. Incredibly difficult (and very risky if messed up), but the results are worth it.
 * He also briefly mixes Sage Mode with his Kyuubi chakra.
 * Izanagi uses both Yin and Yang chakra, . Instead of a Fantastic Nuke, it allows the user to warp reality.
 * In D Gray Man, Allen has the power of Innocence to destroy akuma as well as having powers from an akuma curse..
 * Mahou Sensei Negima
 * Takamichi uses a technique called Kanka which fuses Magic and Ki to dramatically increase the user's abilities, with a stance reminiscent of Gao Gai Gar's "Hell and Heaven" above. (It is even called an "ultimate power".)
 * Not counting Negi himself, who starts to learn Dark Magic Negi's "Dark Magic", however, as described in the supplemental materials, rely upon a long stream of (cited and footnoted) psychobabble that essentially says that, unlike the diametrically opposed Ying/Yang power of Kanka, the darkness of Dark Magic is all-encompassing, and even includes the powers of light. (Including some references to Erebos and Aether from mythology for good measure.) By embracing the all-encompassing darkness, he can still control powers of light, since they do not oppose, but the danger of the spell comes from the way that he stretches his sense of self so thin that he can lose control of his own powers. In chapter 314, Evangeline refers to Negi's way of doing things (not necessarily his magic) as the "gray path".
 * In Yu Yu Hakusho, after, Yusuke
 * Yu-Gi-Oh 5 Ds has grafting the arm containing the fifth Signer mark onto his body once he becomes a Dark Signer. Thus, he becomes a Signer and a Dark Signer at once, planning to use the powers of their respective deities to destroy the world and remake it in his own image. Actually a very extreme attempt for him to Take a Third Option and end the Signer vs Dark Signer battle that has been going on for thousands of years with no end in sight.
 * In Fullmetal Alchemist, Kimblee's prefered attack is this. Each hand has tattooed on its palm a symbol; on his right there is a symbol that stands for the Sun, fire and gold, and on his left one that stands for the Moon, water and silver. When he joins both symbols, the result is this literally.
 * In Fairy Tail,.
 * In To Aru Majutsu no Index, all attempts to allow a person to use both magic and esper powers have ended in failure, except for, and he has to be very careful not to kill himself with his powers.
 * Also, Acqua of the Back has the powers of being a Saint and  a member of God's Right Seat, which would be mutually incompatible if not for a third ability that removes such limitations.
 * In Kenichi the Mightiest Disciple, there are two types of martial artists; Outward focusing Dou types that fight aggressively and turn their anger into a source of power, and inward focusing Sei types, who are calm and calculating and derive their power from inner peace and concentration. And then there is 'Seidou goui', a technique that combines the two for an explosive boost in power but that causes permanent damage to the body if used for too long.
 * In Id the titular character has to negate a Yin Yang bomb twice. The first time, instead of blowing up the continent the energy is used to transport him 10000 years back in time, the second time it conveniently moves him 10000 years into the future, netting in three weeks lived in the past. Later it turns out
 * In Dai no Daibouken this is the basis for Pop's most powerful magic attack, Medoroa: generate fire with one hand, ice with the other, and combine them to shoot a beam of annihilation that can destroy orhicalcum

Card Games

 * In Magic the Gathering there are "white" cards and "black" cards, which are powered by light/life/order and darkness/death, respectively. But printed guides heavily stress that they do not represent "good" and "evil", they can both be used at the same time. A combination of enemy colors in general can be seen to fit this trope, as can cards that are all 5 colors.
 * To wit: Unmake, one of the best removal cards in type at the time of writing, is cast with three mana of either black or white and is considered a black/white card; it had a predecessor in the Apocalypse expansion called Vindicate. Lest we forget, there was also the.
 * Multicolor-focused sets often have White-Black as an option. For instance, in Ravnica, the white-black Guild is The Orzhov Syndicate, who are in charge of business (or, to be more precise, a religion which is also a business), and are run by ghosts.
 * A rundown of enemy-color pairs: White/black is harsh, controlling, and often cruel. Blue/red is high weirdness and mad insight. Black/green is decay, life coming from death. Red/white is an army, equal parts discipline and fury. Green/blue is biology, either mutation or studying new life.
 * The ultimate Yin Yang Bomb is probably the ability on the Legacy Weapon artifact. One mana of each color to exile any single card.
 * Progenitus could also be considered as one, as it takes two of each color mana to summon but is also one of the most powerful creatures in the game.
 * More generally, gold-colored cards that require more than one type of mana to cast and creatures with abilities that require a color besides their own to use have been a staple of the game for quite a while, and are almost always designed to be stronger than equivalent single-color cards of the same cost, since they require you be able to produce multiple colors of mana and thus be more open to resource deprivation. Even before that, players themselves were encouraged to field more than one color to cover the weaknesses built into each one (including spells which can severely handicap a person whose cards are all of one color).
 * The Yu-Gi-Oh! card game plays with this, the main example being the now infamous "Chaos" archetype (which has been banned for years but radically shifted the metagame), consisting of three monsters summoned by removing from play a Dark-Attribute monster and a Light-Attribute monster. One of these, Chaos Sorcerer, provides the page picture. There are plenty of cards that act similar, but the most prominent example is the appropriately named "Light and Darkness Dragon", a monster that has two attributes (Light and Dark, obviously) simultaneously. That and, well, just look at it

Comics -- Books

 * In the Top Cow Universe, the Witchblade is the balance keeper between the forces of Light and Darkness. As a result it has traits of both its parents, the Angelus and The Darkness.
 * Elixir in X-Men has one hand that heals and one hand that kills for his powers.
 * Never aim your urine with the wrong hand.
 * To be fair, he has golden skin (healing ability) with just a black stain (hurting ability). The black stain can move from one spot to another, and doesn't hurt him. Sometimes, the black stain enlarges so much that the entirety of Elixir's body turns black, and may the Maker help whoever pissed him off. It is true, however, that at least in one occasion he (involuntarily) used both his hands (one golden and one black) on the same person, with... unusual results.
 * The 2099 continuity had Xian, who also had the one hand heals/one hand destroys schtick.
 * Magik/Illyana Rasputina tried to be an example (we'll see if she's still trying since coming back to life), practicing both dark and light magic. Sometimes she'd combine the two, like when she attempted to heal someone (light magic) while sitting backwards in a pentagram (dark magic). She kept falling to the dark side, though.
 * During the Princes of Darkness arc of Justice Society of America (back when it was simply JSA), Dr. Fate goes through an arc wherein his powers have been stolen by the Big Bad, Mordru. He finally comes to the realization that he is both Chaos and Order, and so he can defeat Mordru, who is only a Lord of Chaos.
 * On some occasions, the Green Lantern Hal Jordan has picked up Sinestro's yellow ring and used it on combat.
 * The last time he tried during the Sinestro Corps War, Hal put on all the rings that his hands could hold and all-out attacked Sinestro with them. Sinestro just shrugged, took control of all that yellow light and sent back to him. Hal apparently can control fear a bit due to his stint as Parallax's host, but Sinestro has much more experience and control.
 * It's not so much controlling fear as it's the wearer's ability to instill fear in others; hence why Batman was among the first to be offered a ring, his whole persona is based on instilling fear into his enemies. Hal has the same potential, both because many still fear what he will do if he ever wants to regain the power he held as Parallax and also because of the fear he spread while gaining said power.
 * He has also briefly wielded a green and blue together as well that; while they're not opposed to each other, they hold different objectives and their bearers have different methods.
 * Played straighter in Blackest Night, which sees Guy Gardner become both a Red Lantern and a Green Lantern at the same time. Since they were fighting superpowered zombies that could only be destroyed by both a Green Lantern and a non-green Lantern, this is very handy.
 * What made that a Yin Yang Bomb is that Green Lanterns Hal Jordan and Laira had both ended up as Red Lanterns, and had stopped being Green for the duration. Seeing how one is fueled by willpower and self-control, and the other is powered by losing self-control, operating both is probably a bit tricky.
 * Played still straighter in War of the Green Lanterns, in which Guy Gardner manages to wield a red ring and a violet ring together, the two colors at the farthest extremes of the Emotional Spectrum. They represent rage and love, making this the most strongly opposing ring pairing.
 * At one point, a green and yellow ring chose Mother Mercy at the same time, but she quickly decided to reject the yellow ring.
 * In Superman Beyond, Quantum Superman fuses good matter Superman and evil antimatter Ultraman into a hyper-contextual amalgamation of two symmetrical concepts and then they power a giant Superman thought-robot and beat up the personification of Grimdark.
 * Pride High has Lightspot, a faculty member who controls both light and darkness. The darkness power allows him to teleport by traveling through the shadow dimension, which has been hinted to be a very evil place.

Literature

 * Star Wars Expanded Universe
 * Mace Windu's Vaapad form, detailed in Shatterpoint, definitely counts; he refined the lesser lightsaber form of Juyo into devastatingly effective technique by allowing himself to enjoy the fight, which channels the Jedi's aggression but also skirts dangerously with the Dark Side. He was the only Jedi to master Vapaad without succumbing to the Dark Side (although in fairness ).
 * Knights of the Old Republic features a good-aligned Force user with a criminal past who's living in a self-imposed exile from the Jedi Order and draws equally on the Light and Dark sides to accomplish his goals.
 * In the recent novel tie-in to The Old Republic, Revan, when
 * It takes a while to get there, but this trope becomes the entire point of the end of Brandon Sanderson's Mistborn trilogy. The prophecied Hero of the Ages destined to  could be male or female based on the ancient grammar..
 * In addition, this trope is the secret of the immortality of the Big Bad of the first book. The first book reveals two magic systems: Allomancy, which works by ingesting various metals and consuming them to get temporary power-ups, and Feruchemy, which works by saving up a person's own attributes like strength or health in metals and consuming them later in an Equivalent Exchange. Both are Inherent Gifts. Allomancers are generally more dominant in society and more oriented towards combat, but we're told that Feruchemy has its own strengths and weaknesses and can do things that Allomancy can't. In the end,.
 * Defied in The Bible. As 2 Corinthians 6: 14 puts it, "For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness?".
 * It may refer to spiritual light and darkness. But then, people fighting with light and dark powers isn't exactly recorded...
 * Actually, it's an analogy referring to physical light and darkness, not figurative. It's saying that righteousness and wickedness are as alike as light and darkness (meaning mutually exclusive), not that righteousness = light and evil = dark.
 * Ursula K. Le Guin's The Left Hand Of Darkness makes a poem about this (about the larger theme of balance in general): "Light is the left hand of darkness, and darkness the right hand of light." They're one and the same.
 * Thomas Covenant becomes one of these in the second trilogy finale White Gold Wielder when
 * Most of the truly important mages of either faction in the Recluce Saga are gray mages, capable of using both order and chaos magic. These tend to be the most powerful mages in the world in whatever time they happen to live.
 * The Wheel of Time features Mutually-Exclusive Magic of the sort where men and women get their powers from different sources, produce even identical magical effects in completely different ways (most explicitly mentioned when certain people learn how to Travel), and even use opposite techniques to just access magic...but the most powerful magical feats, like or, require the use of female and male magic together.
 * The symbol for the union of male and female magic is itself a simplified yin yang.
 * In Skulduggery Pleasant Valkyrie Cain sort-of becomes this when.

Gamebooks

 * Lone Wolf
 * In book 7, Castle Death, the owner of said castle, Lord Zahda, uses a Lorestone and a Doomstone.
 * Lone Wolf himself can wield a holy weapon like the Sommerswerd and infernal weapons like Helshezag. (Theoritically not at the same time, but that doesn't stop some players to have houseruled Dual Wielding.)

Live-Action TV

 * Common theme in the Robin Hood Robin of Sherwood series. Robin and his sword Albion are specifically said by Herne the Hunter to have the "power of light and darkness".
 * One episode of Charmed had Phoebe and Paige traveling to a Mirror Universe and fighting their Evil Twins. The battle between the two Paiges causes explosions due to their opposing powers colliding. Later, they team up with their evil twins and form "The Power of Four" by combining their powers to devastating effect.

Tabletop Games

 * The Shadow Sun Ninja prestige class in Dungeons and Dragons.

Video Games
"Cecil: (during his EX Burst) Light and darkness cast aloft!"
 * In Terraria, you can explore the blightely dark lands of The Corruption and the joyful, light-aligned Hallow and find respectively Dark and Light Souls, which are used to make or upgrade dark or light-themed equipment. Fuse them with two particular (and rather rare) items and you obtain the Dao of Pow, an Epic Flail which is essentially a huge spiked Yin Yang on a chain capable of massive damage and confusing any enemy it touches.
 * Final Fantasy
 * Final Fantasy IV. The main prophecy speaks of "light and darkness cast aloft". Cecil is pure light at the end of the game, but it does take both him and, still in the dark side, to deal with the Big Bad in the end.
 * Palom and Porom's Twincast works off this concept, as do a couple of Bands in the sequel, Final Fantasy IV: The After Years: Rosa and Rydia's "Holy Burst", Cecil and 's "Ultima Spark", and Palom, Porom, Rosa, Leonora, and Rydia's "Infinity".
 * In Dissidia Final Fantasy, Cecil becomes one, freely switching between Paladin and Dark Knight as he fights.


 * And it gets Lampshaded.

"Jecht: Light, Dark, just make up your mind!"


 * Before this, Final Fantasy III had the Light Warriors unable to defeat the Big Bad without invoking the power of the Dark Warriors, who had previously combatted the unnatural growth of Light (The world now being in an unnatural state of Dark.)
 * The DS version of the game replaced the Mystic Knight class with the functionally identical Dark Knight class. Allowing a Light Warrior to fight with Dark power.
 * of Bayonetta is born of both a Lumen Sage and a Umbra Witch
 * Most main characters in the Persona (or Shin Megami Tensei) series can wield both Light and Dark magic. Curiously, they are both insta-kill magics instead of healing (which most often shows up on Wind or Water Personas).
 * Shin Megami Tensei: Devil Children: Book of Light and Book of Dark (DemiKids in the states) was all about this. The game was One Game for The Price of Two, one "dark" version and one "light" version, which followed one story from two viewpoints, Jin and Akira, also light and dark, respectively. The final boss was in two parts, also one light and one dark. Akira fought the light half, Jin fought the dark half, and the storyline had it so that both were fighting at the same time.
 * Furthersome, Naoto from Persona 4 was practically a pure incarnation of this. Specially considering how in Persona series it's hard to hold both Light and Dark attacks simultaneously.
 * The strongest personification of this trope in the Persona series is Armageddon, the strongest attack in the games doing 9999 non type unavoidable damage to everything or an automatic victory. It is made by combining the opposing aspects of Satan and Lucifer.
 * In the MMO "Shin Megami Tensi" Imagine" They are no longer light and dark, but Death and Expel. In an odd variation, player characters cannot use death or expel themselves. The closest, however, is that they can use both white magic (healing/buffing skills) and dark magic (damage based/debuffing skills)in unison, and each one is a sepearte class, so you could have a person who can both debuff and buff, or in closer symbols for light and dark, revive all party members at full health and then blow up the enemies with a blast of destructive energy. or combinations. Any character who masters two skills that correspond with each other could be considered a non-alignment yin-yang bomb, if you master counter/dodge and a melee based skill you have the distinct possibility of becoming unhittible in one on one combat, however only in one on one.
 * Riku's ending in Kingdom Hearts Chain of Memories and throughout 358/2 Days and Kingdom Hearts II. The ending of the latter may have broken this though; the fans still argue about it.
 * During the last hit of the Eternal Session Combination Attack Limit Break, Sora and Riku charge their Keyblades with Light and Darkness, respectively, and crash them into each other for a superpowerful attack combining the two elements. Some of Riku's sleights in Re:Chain of Memories work the same way, just with Mickey channeling the light power instead of Sora.
 * Xemnas uses a yin-yang bomb style of attacking in the final battle, throwing out beams of darkness and light. Xemnas even trades out his trademark black robe for a robe of black and white swirls.
 * Roxas' element is Light, but as a Nobody he's technically a being of nothingness. Its his two Keyblades that are a representation of the trope, the light-aligned Oathkeeper and dark-aligned Oblivion. Sora's Final Form also somewhat qualifies - it symbolizes him manifesting Roxas' power, and his mostly black outfit takes on elements of Roxas' silver and white clothes, resulting in an outfit covered in white and black swirls. Artwork for Final Form also shows it with the Oathkeeper and Oblivion like Roxas.
 * The Oathkeeper and the Oblivion are obvious if you know Japanese. The Oathkeeper's teeth are the kanji for "light", while the Oblivion's teeth are the kanji for "darkness". Also related is that both of Sora's best friends are each symbolized by these Keyblades; Kairi is light and is represented by the Oathkeeper (the keyblade has her lucky charm as a keychain and is obtained after he got a clue of where she was in KHII) and Riku is darkness and is represented by the Oblivion (he has used the keyblade himself and in both KH and KHII it is obtained after an encounter with him). This is supported by the fact that Riku uses the power of darkness to fight and Kairi is a Princess of Light.
 * If you live outside Japan and haven't looked it up, you'd never know, but in Kingdom Hearts II, Sora gets the Two Become One keyblade after defeating Roxas. The keyblade itself is covered in silver, white, and black sections, symbolizing a combination of Sora's light and darkness (and his combining with Roxas). Its special effect is called "Light and Darkness", which causes him to, when he Drives, become either Final Form, as described above, or Anti Form, a shadowy Heartless-like Sora, no matter which (usually low-cost) Drive form you actually chose. In this case, Final Form represents light, and Anti Form represents Darkness.
 * In Birth By Sleep, Master Xehanort preaches the virtues of this path to Terra, telling him that Eraqus's way of shutting out and killing the darkness is just as wrong as succumbing to darkness entirely, and that the right way to protect the worlds is to wield light and darkness in equal measure.
 * Also in Birth By Sleep, the is a Yin Yang Sword, forged by combining a heart of pure darkness with a heart of pure light.
 * The Shadow Breaker command in Kingdom Hearts 3D consists of two whirling slashes, the first dark element, and the second light.
 * The ending of Tales of Eternia, in which.
 * Judas in Tales of Destiny 2 wields a dark dagger and a light dagger. He also is proficient at both light and dark-type spells, which really doesn't make too much sense, as his elemental affinity is technically Earth.
 * Shing (light) and Kunzite (dark) in Tales of Hearts have a Combination Attack called Senanreppajin - in kanji, "Flash Dark Tearing Break Sword". It's activated by synchronizing two of the best multihit elemental sword moves they have.
 * In the PS 3 version of Tales of Vesperia, Yuri and Flynn's combination mystic arte, Bushin Soutenha, has them team up and fire a beam of intertwined darkness and light at their victims.
 * Illusion of Gaia
 * Jak from Jak and Daxter gains both Dark Eco and Light Eco powers over the course of the story. Though not referring to him directly, he is even told that "the two types, light and dark, when combined form great energies."
 * Ikaruga
 * Metroid Prime 2 gave Samus a Light Beam and a Dark Beam. Later, she put them together into the Annihilator Beam.
 * The Chaos Emeralds in the Sonic games are said to contain both positive and negative energy. Most prominent in Sonic Adventure where the emeralds are drained by Chaos and turn a dull black color; when all seemed lost, someone knowledgeable about the emeralds tells the heroes that only the negative energy was absorbed and they can still use the positive energy. Cue boss fight.
 * Dante of Devil May Cry fame, with Ebony and Ivory. He uses both demonic and human weapons. In the third game, Vergil hates humans, and exclusively uses demonic weapons, and Lady hates demons, and uses ordinary human guns. Dante's usage of both types of weapons proves to be more powerful.
 * Grandia II. Good and evil were necessary to win the game, as you had a holy priestess with you and an evil demon, both in the same person, and you, being the hero, were kind of the neutral mix of both. May also apply to the Big Bad
 * Wisp of Knights in The Nightmare has the power to switch the "Battle Phase" between Law and Chaos at will, which causes its Knights to execute different attack patterns. Also, the amount of Power Crystal (required to Break Out) dropped by enemies depletes over time, but returns to full when the Phase changes, forcing Wisp to switch between the Phases in order to keep up the assault.
 * In Legaia 2, the White Mage turns out to be a powerful sorceress -- much to her own surprise -- and the first special technique she masters is "Big Bang," which combines dark and light forces in an unblockable, non-elemental explosion. Her attack-line is actually "Power to Create! Power to Destroy!"
 * Wes from Pokémon Colosseum, with his Espeon and Umbreon.
 * Solrock and Lunatone, also, who you face in a double battle with Liza and Tate in Pokémon Ruby and Sapphire.
 * Shining Force
 * You need to get the Sword of Light and the Sword of Darkness to use as keys to get the Chaos Breaker, a plot-important Infinity Plus One Sword.
 * If you explore during Michaela's battle, you'll find the White Ring, Black Ring and Evil Ring. Though it may not sound like it, the Black Ring is the Yin Yang Bomb. It's cursed just like the Evil Ring, but it's the only ring that can only be equipped to the hero, and in battle it perfectly complements the White Ring. The Evil Ring is only a Disc One Nuke.
 * Shining Tears has a system where you pair off in battle with a Light- or Dark- aspected partner, and your alignment is shifted to the opposite thanks to your Yin/Yang rings.
 * Soul Calibur
 * One of the weapons for a character was the "good" sword corrupted by the "evil" sword, while the other time, an immortal man brings the two swords together. Bad things happen as a result.
 * And in Soul Calibur IV, Talim's final weapons (she uses a pair of "elbow blades") are Soul Edge and Soul Calibur: one in each hand. Kilik's ultimate weapon is Embrace of Souls, a fusion of Soul Calibur and Soul Edge that leaves both swords inert (though still powerful), in staff form.
 * In Castlevania: Order of Ecclesia, the item crash between a light glyph and a darkness glyph (except for Dominus) results in a literal, and very powerful, Yin Yang Bomb.
 * It's also a Game Breaker. 4 hits of that attack and within 10 seconds you've just beaten the final boss.
 * also uses his "Balance Cannon Shot", firing a light projectile and a dark projectile which whirl outward in a helix. It hurts.
 * The Xel'naga temple in Starcraft Brood War requires both the Uraj crystal, powered by High Templar energies, and the Khalis crystal, infused with Dark Templar power, in order to activate and blow everything within a wide radius straight to Hell on the armageddon express.
 * This wasn't the first time, either. Tassadar channeled High and Dark Templar powers simultaneously to kill the Overmind. (Mind you, having a Carrier take a nosedive into the thing couldn't have hurt.)
 * Technically he didn't nosedive. he used it as a channel device to launch a pulse
 * The Twilight Archon in Starcraft 2 was planned to be this, a combination of a Dark Templar with a High (Light) Templar. Then the unit was replaced by the normal Archon, the only difference is that now it forms as a combination of any two Templar units regardless of their alignment. So it can be a yin-yang bomb, but doesn't have to be.
 * Baten Kaitos inverts this trope. If a character chooses moves with opposing elements in the same turn, the elemental damage cancels out, and the combined result is weaker than an equivalent turn made from moves with non-opposing elements.
 * The prequel plays this straight by revamping the combat system. Several EX Combos use elements opposed to each other, including Guillo's tremendously powerful light and darkness combos.
 * Django of Boktai is of both Solarian and Lunarian blood, which lets him wield light while being extremely resistant to darkness. Nevertheless, he's bitten by a vampire in the second game and becomes "half" vampire. He gains enough control that he can shift between normal and vampire mode at will.
 * This symbolism is broken in the third game where his Karma Meter decreases the more he uses his vampiric self.
 * Done straight in the final boss of the first game and the second to final boss of the second game where
 * Also done straight in Boktai DS (Lunar Knights), where the entire point is for Django and Sabata to work together.
 * Jolee Bindo is a Grey Jedi, and uses Light and Dark powers interchangeably.
 * An even better example is Kyle frickin' Katarn, who can very well be considered a Gray Jedi. One of the first things he taught to his pupils was that the powers they use are neither good nor evil, it's how they use them that is important. The one apprentice who took that lesson to heart has beaten an ancient Sith Lord in single combat.
 * You can use the Player Character as one in Knights of the Old Republic, though it is rather difficult to throw around light-side buffs and neutral or dark-side attack powers unless you are a Consular with maxxed Wisdom and so many force points it isn't even funny.
 * This is a feature of an optional character in Chrono Cross, Pip/Tumalu. You can evolve him as light/light, dark/dark, or light/dark (or dark/light, works the same way). The third is often considered the best standalone.
 * In Seiken Densetsu 3, you get two class changes per character. Similar to the Chrono Cross example above, each time you class change, you can pick either the Light or the Dark advance from your current class, leading to Light-Light, Light-Dark, Dark-Light, or Dark-Dark.
 * A long part of Albion's gameplay requires the player to retrieve two scrolls that together, hold the knowledge to combine magic and technology, which are polar opposites of each other. The end result is
 * In Touhou, Reimu's Yin Yang Orbs are likely the most literal example of this trope one will find.
 * Yukari's power over boundaries seems to be all about this. "Mesh of Light and Darkness" "Curse of Dreams and Reality", "Balance of Motion and Stillness" etc etc. So basically her power is a myriad different Yin Yang Bombs.
 * Dante from Dantes Inferno uses the holy cross and the infernal deathscythe.
 * In Heroes of Might and Magic IV's expansion The Gathering Storm, one of the protagonists uses order and chaos magic together, and his campaign involves seeking a Yin-Yang-related artifact that will power both.
 * Another protaganist is able to use a combination of white magic and necromancy.
 * In World of Warcraft, balance-specced druids switch back and forth between solar- and lunar-based spells as one of their main mechanics. Their signature move, Starsurge, is a powerful blast formed by fusing the power of the moon and sun.
 * Priests have holy spells to heal and buff allies or smite enemies, but also rather evil-sounding shadow spells that can inflict extreme pain on enemies, or liquefy their very mind. They can switch between Shadow and Holy magic at will, but they technically can't use both at the same time. The proportion of "Yin" and "Yang" used so by a priest depends on the amounts of talents he or she has learned in the appropriate spell school, with a Shadow/Holy hybrid spec being the closest thing to a true Yin Yang Bomb. (As of Wrath of the Lich King it's also possible for a multispeccing priest to have a Holy build (usually for healing) and a Shadow build (for damage) to switch between as appropriate, becoming a Yin Bomb or a Yang Bomb as the circumstances call for.)
 * There is also the Mage, capable of casting both Fire and Ice spells.
 * The announced Monk class has a "Light Force and Dark Force" system, in which you use Chi to generate either force, and you can use both.
 * The origin of humanity, and the mortal world of Sanctuary in general, in Diablo.
 * Chrono Trigger has the Antipode dual-tech chain, created by combining Marle's ice magic and Lucca's fire magic.
 * MARDEK: Chapter 3 has Zach's strongest attack, "Immoral Injustice," which deals large amounts of damage to both light and dark elemental foes. The animation looks like a yin-yang. His strongest weapon is a double-bladed sword called "Yin and Yang."
 * Mana Khemia 2 Fall of Alchemy has this as the ultimate Combination Attack of the two leads, Raze and Ulrika (who were granted powers by the Light and Dark Mana, respectively).
 * The XBLA Bullet Hell-infused Platform Game Outland is based around this.
 * In Arc Rise Fantasia, both Dynos and Cecile have an Excel Act each (Doubly Dark and Light and Dark!, respectively) that merges a mass of light and darkness together to form a huge combined beam. Apparently it's a "forbidden art".
 * Magicka gives you lots of opposites. While combining them yourself is impossible, you and another sorcerer can combine opposites (for example, Life and Arcane), which will generate a devastating Antipodal Blast.
 * In Star Wars: The Force Unleashed, Starkiller seems to combine Lightside and Darkside techniques in battle.
 * You run across quite a few Darkspawn Emissaries and Blood Mages in Dragon Age with skill in healing in addition to their darker powers, which makes them much more obnoxious to fight since they've got the Creation-school healing to let them keep throwing out the Entropy-school hexes for longer.
 * In Demons Souls, the greatswords Soulbrandt, which becomes stronger if its wielder's soul is demonic, and Demonbrandt, which becomes stronger if its wielder's soul is untainted, can be forged together into the Northern Regalia, a greatsword that is at its strongest if its wielder's soul is purely demonic or untainted.

Web Comics

 * At the end of the "Storm of Souls' arc, Dominic Deegan had to fight Celesto Morgan, the Champion of Chaos and Darkness. Celesto assumed that Dominic was the appropriate counter for him -- the Champion of Law and Light. But no, he was the Champion of Balance, imbued equally by Light (thanks to his brother, Gregory, a powerful White Mage), Law (through Klo Tark, a master of mind-magic), and Dark (through the Anti Hero Necromancer, Rillian). When Celesto strikes him with an attack concentrating the pure Chaos of the Storm of Souls, Dominic absorbs it. However, it's soon revealed he needs to take it a step further by gaining the physical elements--which provides him.
 * Sinfest depicts the Buddha as a cheerful Cloudcuckoolander that confounds God and the Devil alike.
 * Pella in Looking for Group gives Cale a gift of two swords, named Good and Evil. Cale represents the balance between them.
 * The Tumor in Homestuck is a literal example, being a giant bomb with a black and white coloration similar to the yin yang symbol. Its power annihilates two

Web Original

 * Centigrade, a superhero from the Global Guardians PBEM Universe uses both ice-based powers and fire-based powers to fight crime.
 * In the Sonic the Hedgehog fan flash movie Nazo Unleashed this trope is invoked against the titular Nazo in his Perfect form. After both Super Sonic and Dark Super Shadow get soundly curbstomped one after the other, Sonic (light) and Shadow (...well, shadow) use Chaos Control to merge into Hyper Shadic, who proves strong enough to challenge the "darkness" that is Nazo.

Western Animation

 * Equinox's schtick in Batman the Brave And The Bold, going as far as wearing a Yin Yang symbol on his chest. His costume was half black and half white, and he tried to maintain the balance between Chaos and Order (naturally going insane in the process).

Real Life

 * Most of the universe is composed of Matter. Antimatter is its exact opposite. Mixing the two will invariably result in annihilation, a technical term meaning all their mass is converted to energy (photons). Keep in mind that the energy of an object is the mass multiplied by the square of the speed of light (E=mc^2). You get a very big boom. Fortunately, most of the anti-matter in the universe seems to have exploded already.
 * Which is, by the way, one of the great mysteries of physics. Theoretically, the amounts of matter and antimatter in the universe should have been equal, resulting in complete annihilation of the universe. The disparity of matter and antimatter still puzzles physicists.
 * Not so mysterious anymore, there are several observed phenomenon that favor matter over anti-matter.
 * Thermal shock; super-heat a piece of glass or ceramic, and then quickly introduce it to extreme cold, and watch what happens.
 * Real Life famously mixes good and bad, and would any of us trade it? One might even go so far as to say it's the bomb.