Follow TV Tropes


Mutually Exclusive Magic

Go To

"Since Light and Shadow cannot coexist, possessors of Shadow Magic must first give it up before learning this [Light] magic."

In a fantasy setting, where magic is abundant, a commonly seen rule is that no one can master multiple or opposing schools of magic — ex. one can either learn divine or unholy magic, but not both.

The reasons for this may vary. It may be that the teachers of either school don't particularly get along very well, it may be that the talent for any given type of magic is an inherited trait, perhaps some of the mystical energy a mage uses is left in them and the two energies react to each other in a negative way (negating each other, therefore weakening the mage, or perhaps actually damaging them in some way), or it may simply be that all you used to learn one type contradicts what's used to learn the other, and most people just can't get over that hump. In some settings, this extends to all forms of Functional Magic: Hermetic Magic, Psychic Powers, Ki-powered Supernatural Martial Arts, etc. A Doylist explanation would boil down to some sort of Competitive Balance, to explain why magic users aren't cherrypicking the most useful skills of all schools and instead occasionally have to contend with a Drama-Preserving Handicap.

Depending on the series, it may still be possible to learn multiple schools, so long as they don't oppose each other — One can learn Fire and Wind magic together, but not Fire and Water.

Breaking this forced division is the source of the power of a Yin-Yang Bomb. The Red Mage averts this restriction. Compare Wrong Context Magic and Hybrid-Overkill Avoidance.


    open/close all folders 

    Anime and Manga 
  • In Black Clover, mages are born with only one magic attribute like water, plant, spatial, etc. and can only cast spells of their attribute. The exceptions are hybrids who can be born with two attributes, mages who have been experimented on, and hosts of high-ranking devils who gain the magic of their devils.
  • Bleach:
    • Hollow and Soul Reaper powers. Technically, they're supposed to be polar opposite types of abilities (although Hollow powers don't receive as much explanation), but certain characters have gotten around these limitations. The Arrancar are Hollows with Soul Reaper abilities, while the Vizard are Soul Reapers with Hollow powers.
    • Quincy vs. Soul Reaper abilities; Soul Reapers use their own spirit energy and can focus it with a magic sword. Quincies use the free floating energy in the world, and can focus it with a magic trinket. Ichigo has both due to his heritage.
    • Quincy vs Hollow powers appear to be this. Quincy powers destroy souls and Hollow spirit energy is toxic to Quincies.
  • Clow in Cardcaptor Sakura was able to combine Chinese and Western magic, which were previously thought to be incompatible.
  • A Certain Magical Index:
    • Esper powers rely on creating a "personal reality" and imposing it on the world, while magic relies on inviting concepts with heavy memetic weight (such as deities and popular stories) into the user's body to gain their power. Once a person has been trained as an esper, even if they have no real powers, they cannot use magic without disrupting their personal reality and causing massive hemorrhaging. One esper in the series is able to use magic anyway because his esper ability happens to be a mild Healing Factor, another manages to pull it off by focusing all his esper abilities on holding his body together, and a third is a Cyborg who negates the damage by displacing it to parts of her body which no longer exist. Mikoto Misaka, meanwhile, is able to use magical Powered Armor due to both her esper ability giving her the mastery of the tech while the "magical" part is technically indirect via special runes enchanted into the machine. Even then, she still gets nosebleeds if she uses it too long unless she has fellow Level 5 esper Misaki sharing the mental burden with her. Magic is said to have been created for people who couldn't use esper powers, back when they appeared only by chance.
    • The mages of God's Right Seat each wield an enormously powerful divine ability themed after a different archangel, but in order to do so they had to give up their ability to use standard magic. This is a bit of a problem for their leader, who needs some standard magic to enact his grand master plan. The process by which they gain their powers actually functions in the same way as the esper training curriculum, and may have been the basis for it. One of their number, Acqua of the Back, is an exception due to also being a doubly-blessed Saint with the Adoration of Mary, which "forgives" him of the penalties for using conflicting powers together. While never mentioned in the series, this also hints he could develop esper powers without issues as well.
    • The main character Touma has Imagine Breaker, the power to negate any and all supernatural powers. For this reason, it's impossible for him to use magic or esper abilities.
  • Ripple/Hamon in JoJo's Bizarre Adventure is based on channeling one's own life functions (specifically, respiration and flowing blood) and often described as The Power of the Sun. This is why it's so effective against vampires, who gain strength by draining life from others and are killed by the sun. When Straits became a vampire then channeled Ripple energy, it destroyed his body completely — which was his intention. Once Kars removes his weakness to sunlight, he's able to use Ripple without harming himself.
  • Kenichi: The Mightiest Disciple has Sei and Dou ki. Each describes the fundamental trait in a person's fighting style; basically whether they fight with their head or with their heart respectively. They can be mixed, it just causes horrible internal damage and fun stuff like your eyes possibly rupturing. At first they both basically do the same thing anyway, but, at higher levels Sei and Dou ki can trend towards Personality Powers. Sei users tend to develop Awesomeness by Analysis skills like the Ryuusui Senkuken while Dou users have explosive power and can dish out the seriously hard hits.
  • Magi: Labyrinth of Magic: Magicians aren't capable of using Household Vessels because they are already versed with normal magic, and that uses the same process of magoi manipulation that allows Household Vessels to function.
  • Negima!:
    • Negima! Magister Negi Magi:
      • Ki (drawn from inside the user) and magical power (drawn from the user's surroundings) are opposite, and trying to use both at once usually ends with Stuff Blowing Up. However, Negi himself gets around this by using magical power as a substitute for Ki in his martial arts techniques while still using it to power his spells as well. Additionally, there's a special technique which fuses Ki and magic to strengthen the user's body, but it's notoriously difficult and only three characters in the setting have been shown to use it, one of whom only uses it because he can't use magic anyway.
      • If one pursues the normal course of power to the upper levels of strength by following the 'light' path, they become unable to use dark magic. To be more accurate, they can use it, but the results will be very bad: While Jack Rakan is technically capable of using Eva's Magia Erebea, doing so causes a destructive reaction that injures him far worse than he expected, though he laughs it off. However, approaching from the other side, someone who uses Magia Erebea can still use light magic because it's less the darkness of evil than the darkness of the void, which is all encompassing. The reason more people don't use it is because of the nasty side effects: Generally, humans can't handle that much dark energy, which can have severe effects on the mind and soul.
    • In UQ Holder!, someone tried to get around this by creating an Artificial Human infused with Light and Dark magic. The attempt was a failure: the magics cancelled each other out and that's why Touta cannot use magic.
  • One Piece: A being can only eat one Devil Fruit in their lifetime, and eating a second will kill them. The fact that Blackbeard, who already ate the Dark-Dark Fruit, was able to eat and use Whitebeard's Tremor-Tremor Fruit without any repercussions, is why he is a notable and terrifying exception in the story.

    Fan Works 
  • In A Certain Infinite Possibility, Teikotu Kakine is able to join the list of espers capable of wielding magic by using his Dark Matter ability to create clones of himself out of Dark Matter that has been been given the properties to defy the laws that would cause the fatal hemorrhaging. It's implied it took a few hundred dead clones before he finally got the formula down so that they wouldn't die casting their first spell and further testing before he could actually make the process cost-effective.
  • In The Death God Alliance, Egyptian magic and Greek magic are described as radio frequencies unable of synchronization. An Egyptian god trying to take a Greek demigod as host will only manage to fry their brain, and the best result was Cassandra becoming a Mad Oracle after taking a minor goddess into herself while she already was the Oracle of Delphi. Until Anubis accidentally fuses his divine essence with Nico's soul.
  • In The Dragon's Son, Tikki explains Quirks interfere with Miraculouses unless the powerset is perfectly matching, and it's far better to entrust a Miraculous to someone with a very weak Quirk or entirely lacking one.
  • Dungeon Keeper Ami is connected to the dark gods' realm via her Dungeon Heart, giving her a constant flow of their power. As a result, she's unable to use the light gods' power at all; just being near it makes her highly uncomfortable, and entering a light temple burns out her Keeper powers for several hours — even though the light gods are sympathetic to her plight. She's also unable to pass through Hero Gates.
  • In The Echo Ranger, a Power Rangers and My Hero Academia crossover, Ranger powers won't work for anyone with a Quirk. It is speculated that combining them might result in a destructive overpowering of the user. It may have something to do with the Rangers-type villain responsible for Quirks calling himself the anti-Ranger. In the end, Power Coins/Morphers refuse to activate for a Quirk user, so reasons are harder to investigate and results are unknown.
  • Trying to mix Geass and Stands in the same mind causes a fatal Brown Note in Lulu's Bizarre Rebellion, though apparently one person once managed to find a way around it. That person, of course, was Dio Brando, whose Stand allowed him to transfer the Brown Note effect to others while remaining unharmed.
    • However, the effect only happens if the person in question is actually processing the information from their senses. A comatose person can combine them just fine as long as they're asleep.
    • Whatever Code-R did to Kewell let him use a Stand and Geass simultaneously, but also shortened his lifespan and drove him insane. The Pillar Man blood probably had something to do with both effects.
    • As Anubis demonstrated, the effect is considerably more permissive about sharing the same body.
  • In Master Potter of Kamar-Taj, there seems to be a distinctive difference between "wizardry" and "sorcery." Sorcery is practiced by the Masters of the Mystic Arts, is Eastern in origin, can be practiced by anyone, is very combat-focused and meshes well with modern technology. In contrast, wizardry is practiced by magical communities all over Europe, is Western in origin, can only be practiced by those with a natural affinity for magic (and even then they usually need a wand to perform spells), is much more mundane and archaic and in fact hampers muggle technology.
  • My Hero Playthrough: Ki and Psionics are are this. Using them together provides an amazing boost of power, but dangerous feedback.
  • Oversaturated World: Oversaturation: Just from their names and how they're never in the same person at one time, Chaos / Disharmony and Harmony magic are implied to be one per person.
  • Remnant's Bizarre Adventure: Semblances and Stands are treated as exclusive due to the effects they have on the users soul and aura, with Bruno telling Roman that using a Stand Arrow on a person with activated Aura has a higher death chance than a person without aura.
  • In Shinji and Warhammer40k, psychic energy and the AT-field oppose each other.
  • In the Fullmetal Alchemist and My Hero Academia Fusion Fic Quirky, Ling Yao is born with a Quirk that that lets him see the best in the dark. When the Homunculus Greed (powered by a Philosophy Stone and human souls) is given control of his body, he can't use Ling's Quirk despite it being a physical trait, meaning he has to lend control to Ling so they can use it.
  • Spellbound: A Miraculous is meant for humans, who have very little natural magic in them, just enough to have souls; the power of a Miraculous temporarily floods the person's body to bring about their transformation. The more innate magic someone gains, the less room there is for the Miraculous magic, and the less strength and toughness they will gain from the transformation. This is why out of the two half-Cat Sidhe Agreste twins, Adrien, rather than Félix, wields the Black Cat ring. Until he absorbs more of Plagg's power as a desperate last resort to rescue Marinette from the fae, and becomes too magical to ever wield a Miraculous again, leaving Félix as the only feasible choice.

  • As a recurring motif of modern Russian-spoken fantasy, the volhvy (Slavic pagan druids) were limited to spells and abilities of their respective deity. In settings with advancing monotheism adopting the "old way" (paganism) and adopting the "new way" (White God, Savior, Light God, various other Crystal Dragon Jesus ideas) are also mutually exclusive.
  • In the Apprentice Adept series, though magic is derived from a single source - Phazite - there are many mutually exclusive ways to invoke that magic: Protagonist Stile (The Blue Adept) utilizes rhyming spells and music, Adept Yellow uses potions, Red uses amulets and talismans, White uses runes and sigils, etc. The only exception is if someone is using the Book Of Magic, which gives even non-humans Adept-level power in ALL the disciplines.
    • More specifically, the Book consists of spells simultaneously utilizing multiple forms of power invocation, organized to efficiently maximize its user's potential capabilities with as little perusal time as possible. While its spells are superior to Adept-style equivalents, and are inclusive enough to make its user a match for one, the Book also isn't up to teaching Adept-level skill in any specific magical form.
  • Since Chrestomanci has the job of overseeing all forms of magic use, his training requires that he learn about all of them, and preferably how to do them. However, candidates for the post are chosen for their strong natural talents as an Enchanter, and they find it extremely difficult if not impossible to perform magic in a way not natural to them. This is mostly because Enchanter magic shortcuts past most of the annoying parts, so when trying to do magic in another way an Enchanter is forced to take unnecessary steps.
  • In John C. Wright's Chronicles of Chaos, the types of magic run on immiscible paradigms. To even understand how another person's magic work, you would have to think the same way, which would stop you thinking your way, and so you would lose your paradigm's magic. (It's also referenced in other, subtle, ways: The group is relaxing at one point, so one of them is performing an experiment where an object can be accelerated to light speed; since his test is "Newtonian", it's something he can easily do. He ends up telling one of the others to go away- she believes in General Relativity, and is causing the item to increase in mass and require more input energy the closer it gets to light speed, just by standing next to him.)
  • In V. Zykov's Conclave of the Immortals the Mass Super-Empowering Event hitting the small city of Sosnovsk produces several types of powers in humans. The known powers of the Skinwalkers (combat shapeshifting), Dreamwalkers (interaction with minds and spirits), Tamers (animal communication and control) are mutually exclusive and apparently exclude the powers of priests and the powers of various other magical species.
  • Cradle Series: Sages are those who have mastered the powers of one or more Icons, while Heralds are those who have merged with their own Remnant. Exactly why these powers are mutually exclusive is unclear, but one girl who was touching on an Icon became a Herald and suddenly lost that ability. Most people who try to combine the powers die horribly. However, combining them is the secret to becoming a Monarch.
  • The Dresden Files: According to Word of God, you can't have Summer and Winter magic. Theoretically, you can, but it's like having matter and anti-matter. Presumably, similar things would happen if you tried Soulfire and Hellfire.
  • Glinda of Oz: The domed island-city of the Skeezers is raised and lowered in the lake where it is located via mechanical magic, which is incompatible with Ozma's fairy magic. And so when the city is submerged and its creator-Queen is turned into a swan, visitors Ozma and Dorothy are trapped there.
  • Played straight in The Legends of Ethshar series. The primary restriction on magic-users is that the source of each type is different. Theurgists pray to gods; demonologist bargain with demons; sorcerers manipulate talismans; wizards manipulate reagents; witches manipulate their own magic; warlocks manipulate a foreign magic. Learning how to use even one school can take a lifetime so very few have the ability or interest to try and study another school.
    • It has been noted that many warlocks were originally users of other magics, but either lost the ability or interest to use their original magic during the Night of Madness.
    • While Wizards are incapable of using any other kind of magic, they are powerful enough to make it illegal to practise multiple forms of magic (or to practise magic while a noble) on pain of death - with the Wizard's guild as judge and executioner. The boundaries between magics aren't always clear-cut either - some therugists occasionally find prayers answered by demons, and both Witches and Herbalists brew potions.
  • The entire plot of Master of the Five Magics is a subversion of this trope. No one in the world believes that anyone can learn more than one type of magic, but Alodar not only learns the basics of all five, he manages to combine them. However, it's played straight in the sequel, Secret of the Sixth Magic: the "sixth" magic is an entirely different order of ability by which the wielder can manipulate magic itself, and anybody with an aptitude for it will fail at any of the ordinary magics.
  • Averted in the Mistborn trilogy. An Allomancer burns metals to fuel superhuman abilities, a Feruchemist stores his own abilities in metals and uses them later, but it's entirely possible to inherit both.
    • This is actually played quite interestingly in-universe; Feruchemical powers are native to the Terris people, and Allomancy is native to the Imperial nobility. The Lord Ruler went to great lengths to keep these groups from intermingling so that the magic stayed mutually exclusive because he was a full Twinborn- in other words, he had all Allomantic and Feruchemical powers and didn't want to risk someone else like him arising. Later on, in The Alloy of Law, bloodlines from the world's various racial and political groups has started getting a lot more intermingled, so Twinborn who have one Allomantic and Feruchemical power each are rare, Compounders who use the same metal for Allomancy and Feruchemy are rarer still, and Mistborn (Allomancers who can use every metal) are basically extinct.
  • Subverted in The Monarchies of God. Tradition holds that there are seven distinct disciplines of magic, and anyone who masters at least four is considered a full wizard. Nobody can master more than six, however, because the seventh is lycanthropy, and fuelling the werewolf transformation ties up the rest of the body's magic and prevents the werewolf from using any other discipline even if they know how. However, Big Bad Aruan is a werewolf archmage who figured out how to use his transformations to fuel his other forms of magic rather than inhibiting them, making him supremely powerful. His followers are also mostly composed of lycanthrope mages with whom he's shared the secret.
  • The Night Angel Trilogy: Averted and played straight. Kylar thinks this is true racially, as people from one country use only healing magic. Durzo explains that hundreds of years ago, those very same healers gave up Black Magic after using it for ungodly powerful things. As a result, the problem is no one will teach them how to use Black Magic in their own country, not that they can't use it. It's played straight with the existence of Male and Female specific abilities (with uncommon exceptions) and the Vir. But you don't want to know about the Vir.
  • In The Obsidian Trilogy, the highly ritualized High Magick of the City of Armethalieh is opposed to the Wild Magic practiced elsewhere. Despite what the High Mages think, it's revealed that High Magick grew out of a specialty of Wild Magic designed for warfare, and while they're too different for someone to be good at both, mages of each discipline can work together.
  • The Old Kingdom series has Charter Magic and Free Magic. Charter Magic is the more organized and academic sort of magic - a mostly rune-and-spell based system that draws on the Charter, the cosmic document that provides order to the universe. Magical creatures found in nature, anything to do with the Dead, and certain human sorcerers use Free Magic, a much more chaotic and destructive power that while not necessarily evil is always extremely dangerous. The only person who practices both is the Abhorsen, who uses necromancy (a normally Free Magic based power) coupled with the Charter to combat dangerous Free Magic creatures and the undead. The prequel Clariel explicitly shows that the two forms of magic and the mindsets needed to wield them are so opposed that advancing too far in one will actively prevent you from using the other, even for an Abhorsen if they dig too deep into non-necromantic applications of Free Magic.
  • Magicians in The Paper Magician must bond with a single specific man-made material (paper, metal, glass, etc.) and then channel all their magic through that material. A magician who has bonded with one material cannot work with any other.
  • A similar thing happens to Pug/Milamber over the course of the many books of The Riftwar Cycle. Having studied, at first unsuccessfully, under a practitioner of 'lesser' magic, he finds it much easier with 'greater' magic, but later is able to use both, as well as elven magic and more, saying that in fact magic is just magic, and the only limitations lie with the user. That is, most people find they can only go down one path, but some can handle more.
    • Then there's Nakor, who rejects the term "magic" in its entirety, let alone the distinction between branches of magic, and claims that all there is to it is a few simple "tricks" anyone can learn which lets them "move stuff around". Nakor is a Cloud Cuckoo Lander of the highest order, but also one of the half dozen or so most powerful magicians in the Multiverse, so whether he is right or not is a bit up in the air.
  • The Saga of Recluce has order magic and chaos magic, and almost always a mage will only practice one or the other. This is because most mages channel magical energy through their bodies, and some of the energy from each spell stays behind in the body; if a mage casts a order spell and then a chaos spell, the residual order energy will react in a painful (or lethal) manner with the new chaos energy. Mages who learn how to channel energy without the energy passing through their bodies can use both types of magic, but knowledge of how to do this is rare, since both order mages and chaos mages tend to be dogmatic about their type of magic being the best.
  • In the Second Apocalypse, knowledge of sorcery is jealously guarded by the Schools, which are divided up in categories based on the type of magic they use (primarily Gnostic and Anagogic sorcery). There's also the Tekne of the Consult and the Psûkhe of the Cishaurim (who technically aren't a School according to the characters, but whatever). At the beginning of the series, there's no known example of a person capable of using more than a single type of sorcery, even though hypothetically there's nothing about the magic itself stopping them, simply because a) you have to join a School before they'll teach you anything, and b) no School would ever give away its sorcerous secrets to someone who has already joined another School. Kellhus dispels the idea that you can't learn sorcery without joining a School when he convinces Achamian to teach him the Gnosis, and being the master manipulator that he is, he could certainly convince another School to give up its secrets to him—but the Gnosis is insanely powerful compared to all other forms of sorcery, so there wouldn't be much point.
  • Vadim Panov's Secret City series of novels has 2 fundamentally different types of magic. The first is using a mana, usually from a Source - some sort of mana-reactor, as used by the Great Houses and the Houses of Asur, Chel and Tat'. White Ladies, human Churches, Masan clans, Hyperboreans and uninitiated humans don't have dedicated Sources, relying on more complex or obscure ways of obtaining mana. The Geomancers are of completely different league - their gift is exclusive with casting traditional spells, instead they make a lot of small changes in the world, which results in some sort of reality warping with any effect the Geomancer wants, even unachieveable with traditional magic. Galla's Heresy is closer to the first type, since it is a type of Anti-Magic with a Source, while The Kitano School is closer to latter - they train Anti-Magic warriors by changing the way magic flows around them. The distinction isn't absolute, since artifacts and golems can be mostly used by anybody, and greatest (and mostly lost or forbidden) wonders were made by combining Source magic and Geomancy.
  • In The Secrets of the Immortal Nicholas Flamel, it's completely possible to learn all four types of magic, but only The Chosen Ones can use two at once; and, once they've learned the traditional four, they are the only ones who can learn the fifth type: Aether.
  • In Skulduggery Pleasant, mages can be either Elementals or Adepts but not both, and once you decide you're pretty much stuck with it as while it's possible to switch disciplines it's very difficult. The title character Skulduggery Pleasant happens to be one of the incrediblely rare few who can use both Necromancy (an Adept discipline) and Elemental magics.
  • Steel Crow Saga: It's theorized that Shadepacting, metalpacting, and Dahali magic all draw on Soul Power, but adopting one form of magic "specializes" the user's spirit to make the other forms inaccessible. Subverted when Tala and Jimuro each spontaneously use the other's form of magic in life-and-death emergencies for the first known time in history.
  • Downplayed in Sunshine: It's technically possible for people to have both magic-handling genes and non-human ancestry, but the combination almost always drives them violently insane as soon as their magic awakens, so they have little opportunity to enjoy the benefits.
  • Sword of Truth: Sorcerers' and wizards' magic is completely different, such that neither can affect the other. This takes the sorcerer Brother Narev by surprise when he tries to kill Richard with magic, who's a wizard, something he doesn't know. Richard then takes advantage of his surprise and kills Narev using a sword.
  • The Unexplored Summon://Blood-Sign has two types of magic-users, summoners and vessels. Summoners call in a supernatural being from another world, which possesses their partnered vessel. Being a vessel requires a special talent — essentially, being easily possessed by spirits. There's nothing inherently impossible about someone with a vessel's talent being a summoner, but it is extremely dangerous, as they will be influenced by their own summoned being. There is one exception to this, a summoner who takes advantage of this to be utterly unpredictable in a fight.
  • Uprooted: A soft-separation is seen. Some wizards and witches, like the Dragon, use mathematically-precise spells and incantations. Others, like Agnieszka, work it in a more organic and intuitive fashion with the results never quite the same thing twice. Combined, the result is greater than the sum of the parts (Agnieszka describes it as a river driving a waterwheel), but Dragon's initial efforts to teach her his way is a huge exercise in frustration for both of them.
  • In Valentin Ivashchenko's Warrior and Mage, learning the ways of the divine magic effectively prohibits the priest from learning arcane magic; non-human species don't possess divine magic. Arcane mages are born with certain affinities, referred to by color. While mages can exhibit multiple colors, e.g. red + dark blue = fire-lightning mage, there were no known black (necromancy) + anything mages.
  • In V. Zykov's Way Home series, the magics of dragons, reptarkhs (sentient anthropomorphic reptile species) and reptohorses (sentient reptiloid centaur species) are mutually exclusive, but can be combined with modern magic. Empowerment of an individual by draconic, reptarkh and reptohorse sources has been lethal with a single exception.
  • In The Wheel of Time series, magic is powered by the One Power, which has male and female halves. Male and female magic-users can accomplish the same things, but more often than not by different methods. For example, the best way for a man to put out a fire is to take the heat from the fire directly but the best way for a woman to do it is to use air or water to snuff it or quench it.
    • The differences are really interesting in that men generally are nearer to a scientific handling of the problem, while women take a more "esoteric" route: Dousing a fire is done by separating heat and fuel, men simply do that while women take the roundabout way. Making portals: women induce a "sameness" in two different places, men take the plane the two different places are on, fold it, so they lie on top of each other, and punch through (basically an einstein-rosen bridge, also known as a wormhole).
    • Ultimately, the truth is inverted, as male and female channelers can link to give one person control of both the male and female versions of the power. Doing so has the combinatorial effect of a Yin-Yang Bomb.
    • A major conflict in the setting is by a few mages in-universe trying to avert this and find a source of magic that could be cast by both sexes. Good news: they found it. Bad news: it unleashed evil.

    Tabletop Games 
  • In Aberrant and Trinity, the same genetic predisposition gives rise to Novas and Psions, but the energies involved interfere with each other. Not only can an individual use only one type of power, but a Nova and Psion in close proximity will actually interfere with each other's powers. In addition, a Psion can only use the Prometheus Chamber, which awakens their psionic abilities, once - trying to use it again has killed every single Psion who's tried it - so they can only have one psionic specialty; you can't be both a vitakinetic and a telekinetic at the same time, for example.
  • In Age of Aquarius, magic schools are based on sets of belief, and that's why you have a hard time trying to combine belief in Goetic demons, for example, and Viking gods to mix Hermetic and Runic magic. It's possible to believe in an All Myths Are True world in this setting, but it will result in a really weak form of Post Modern Magic.
  • Anima has several paths of Magic (with Low Magic Paths being based on standard Elemental Magic like Fire and Light, and High Magic Paths being more metaphysical concepts like Life, Essence, and even Necromancy), and a mage can learn several paths. However, trying to learn an opposed Path to one you already know doubles the costs of advancing in BOTH Paths. Necromancy, as a perversion of magic, is opposed to every other path.
  • Downplayed in Ars Magica: it's possible but quite difficult to learn Hermetic magic, the standard in Western Magical Society, alongside other types of magic. The tutor needs to pass a challenging skill test to teach it without ruining the student's preexisting magical abilities.
  • In several Palladium Books tabletop RPGs, but most explicitly in Beyond the Supernatural, psychic powers require the permanent expenditure of magic energy to develop. As a result, psychics have little magic energy left over for casting spells...unless they're Mystics, who can use both.
  • In the Chronicles of Darkness, a character cannot have multiple Splat templates. A vampire cannot Awaken, a changeling cannot be Embraced, and so on.
    • Mage: The Awakening downplays this with Inferior Arcana. A Mage can still use the Inferior Arcanum of her Path, but suffers penalties for doing so and cannot learn beyond the second dot without the aid of a Mage for whom that path is not Inferior.
    • Thaumaturges from the supplement ''Second Sight' can only practice one magical tradition at a time. Changing is possible, but you forget all your previous spells doing so, even if the tradition you move to has an equivalent.
  • Dungeons & Dragons:
    • Specialist wizards cannot learn spells from their "opposition schools" (which were either fixed or chosen by the player, depending on edition). However, most mages can learn any spell; they just don't get the bonuses that specialists do.
      • In the Pathfinder rules (which are a continuation of 3.5 D&D), specialist mages can learn spells from their chosen "forbidden schools", but preparing a forbidden spell takes up two spell slots. The Thassilonian Specialist, however, goes back to 3.5 type and loses access to spells from their two "forbidden schools" permanently.
      • In 4th edition, the whole practice of specialist wizards was removed entirely and it was purely player theming.
      • In 5th edition, all wizards automatically specialise, but this trope is averted. It's easier to learn their own school, but there's nothing stopping them from learning any other school.
      • 3.5 had a feat chain that culminated in gaining full access to one opposition school, though since Diviners were the only ones to only gain one opposition school other specialists that went for the chain still had a school they couldn't use.
    • While not fully incompatible, in the classic versions magical creatures and magic users are less likely to discover psionic talents, while psonically powered creatures tend to be resistant to magic and have a hard time studying it.
    • Forgotten Realms after Karsus's Folly has Weave and Shadow Weave split as two independent power sources, controlled by warring goddesses. One can't use both and when magic from both in raw form collides, it causes large-scale unpleasantness such as planar rifts. Also, Phaerimm magic and Sharn magic are so non-standard and incompatible that their spells interact violently, changing the landscape.
    • In Dragonlance magic comes from the trio of moon gods, and while it's not technically incompatible, the leading wizardly organization enforces the split into three Orders.
    • Due to game mechanics (mainly ability scores and class levels) it's difficult to master multiple types of magic. There are prestige classes that help avert the trope, but only a few combinations come anywhere near being optimal.
    • Dark Sun averted this trope in the 2nd Edition version. You cannot become an epic level spellcaster unless you're also psychic, because you need psionics to fortify your mind to call upon such magical power. This requirement is even plot-relevant sometimes.
    • In 2nd edition, alignment restrictions on character classes made it impossible to learn both druidic magic and clerical magic.
  • In Exalted, Sorcery and Necromancy are opposed, being based on manipulating Creation's living Essence and the Underworld's entropic Essence respectively, and any given Exalt type will have a higher affinity for one or the other, having access to spells one circle lower for their tier in the case of their lower affinity.
    • Infernals of both types (Green Sun Princes and Akuma) are unable to learn sorcery in the standard sense (that is, as normal Exalts of their type). Instead, their sorcery is channeled through initiation charms specific to each Yozi, which has limits and enhancements on the types of magic they can perform.
    • Alchemicals are unable to use either sorcery or necromancy, but instead have access to another kind of magic called Pattern Weaving, which only they can use. It is possible for them to access sorcery and necromancy, but only by using Voidtech and sacrificing their knowledge of Pattern Weaving.
    • For Celestial and Infernal Exalted, it is possible to cast both sorcery and necromancy spells, even if it is not at equal strength. They are truly mutually exclusive for enlightened mortals, God-blooded and Terrestrial Exalted, who can learn either sorcery or necromancy, but never both. For enlightened mortals, which one they learn is a matter of choice, for God-blooded and Terrestrials, it is determined by birth.
    • The Deal with the Devil process of becoming an akuma consists of infusing the magic of the Yozis into the recipient. It fails automatically on Abyssals and Alchemicals, who are already infused with the magic of different Primordial-level entities and are thus unable to add Yozi Charms to their sets.
  • Frostgrave has ten schools of magic; each school is aligned with several others, neutral to most of the rest, but has one that opposes them. There are increasing degrees of difficultly in casting spells outside of your school, with aligned being the easiest and opposed being the hardest.
  • A Pyramid article about crossovers between GURPS Technomancer and other settings says that a Mage: The Ascension crossover is possible with both magic systems running in parallel, but that a character with GURPS Magery should not be able to Awaken, and vice versa.
  • In the Savage Worlds: 50 Fathoms campaign setting, mastering more than one element gives you spellcrafting penalties as the elemental spirits governing your magic conflict with each other. Until you've mastered all four, at which point the spirits are in balance and stop fighting.
  • In Shadowrun, mages learn magic through a Tradition, which is basically your belief of how magic works and where it comes from. Since magic is fueled by belief and Doublethink isn't conducive to good magical praxis (or one's sanity), magicians are usually stuck with the Tradition in which they were trained. Depending on edition, your Tradition would restrict your magic in some way; in the first three editions only Hermetic Mages could cast spells and only Shamans could summon spirits or have a mentor, while in later editions Traditions determined what sorts of spirits one could summon and the manner in which one resists Drain.
  • A general rule in Unknown Armies. Becoming an adept requires an insane devotion or obsession with a concept or school of thought, and that sort of focus can never be divided. Becoming an avatar requires that a character follow the specific mindset of an archetype, almost all of which are mutually contradictory. Very rare individuals can juggle both avatar and adept obsessions, or multiple weaker adept obsessions, but the results tend to be so far off the crazy charts that they're closer to forces of nature than characters. The one built-in exception is avatars of the Mystic Hermaphrodite, who are living embodiments of ambiguity and uncertainty; they can be adepts as well, so long as their chosen path isn't built on logic. For example, they can be epideromancers (based on Self-Harm) or entropomancers (based on gambling), but not bibliomancers (based on books) or urbanomancers (based on living in a city).
  • The Warhammer universe has magic powered by the 8 Winds of Magic. It's not impossible to use spells powered by different (or even multiple) Winds, but unless you're an elf, or some form of Chosen One, Bad Things tend to happen. Intriguingly, Rainbow Wizardsnote  tend to have serious trouble learning and casting spells from the Lore/Wind in opposition to their own, while Highnote  and Dark Wizardsnote  don't have this problem, no matter which Lore they originally learnt.

    Video Games 
  • In Age of Wonders your leader can choose only non-antagonistic magic spheres.
    • In Age of Wonders 2, you can either choose all of them, giving your wizard a random selection that often ends up game-breakingly good or bad, or a single sphere. Notably, no matter which you choose, you can still buy/find/receive any spell. Also, Common sphere spells always can be researched and Secret sphere never.
    • In Age of Wonders: Shadow Magic, you can either pick a single school or massively gimp yourself by taking multiple schools, ensuring that you never get any powerful spells.
    • Age of Wonders 3 allows you to chose up to 3 specializations for your leader, which means that you can have spells from the schools of Creation and Corruption or Water and Fire at the same time. However doing so only allows you access to the most basic spells from that school. You are also allowed to "Master" a school, which gains you access to the best spells it has to offer but costs you another specialization point, meaning you can never Master more then one school at a time.
      • In addition, each class has access to a number of unique spells, which are naturally mutually exclusive with those of other classes. Unlike traditional magic spheres, there is no way to obtain class-specific spells from quests or treasure sites at all.
  • The different forms of magic in the Dark Souls series all operate differently and have different origins.
    • Miracles are a light-based magical art founded in Anor Londo. The effectiveness of miracles are contingent on the faith of the user (the only exceptions being miracles associated with Velka), and descriptions of the miracles state that the art of miracles were founded by Gwyn, Lord of Sunlight and his pantheon. Miracles are largely utility spells focusing on defensive purposes such as healing, deflecting, and augmentation with few providing pure damage. Unlike sorcery, offensive miracles can deal lightning damage in addition to magic damage.
    • Pyromancy was a magical art founded by Quelana of Izalith (the "Mother of Pyromancy"), one of the daughters of the Witch of Izalith (the "Godmother of Pyromancy"). Seemingly a power inspired by the First Flame and the Lord Soul that the Witch had found, pyromancy is elemental magic based around the creation and manipulation of fire. It requires equal parts a certain level of faith and intelligence to wield, and the user must have access to pyromancy flame. It is considered "crude" and "uncultured" compared to other arts and thus much of its techniques are founded in the great Swamp where Quelana lived in self-exile. Practitioners of pyromancy are alternatively called "pyromancers" and "flame sorcerers", though a distinction is made in that "flame sorcery" is what the Witch practiced (and have died when she became the Bed of Chaos), thus making it a precursor art to pyromancy.
    • Sorcery is a magic art that relies of intelligence to wield. It was founded by Seath the Scaleless, itself a by-product of his attempts to properly research and harness the power of the Primordial Crystal that gave him is crude immortality. Because of this, sorcery is often attributed with a crystal-theme to it. Another recurring factor to sorcery is that many of its practitioners (Seath, Big Hat Logan, Oceiros, etc.) end of devolving into madness, implied to be a case of Go Mad from the Revelation since sorceries are contingent on intellect.
      • Various subcategories of sorcery have been created from (or may be cousin to) Seath's research, Dark Sun Gwyndolin skilled in moon sorceries, dark sorceries inspired (possibly created) by Manus, Father of the Abyss, and ice-based sorceries being used by inhabitants of the Painted World. It is unknown if the flame sorceries that the Witch of Izalith and her Daughters of Chaos wielded is in anyway related, but considering that the crystal was given to Seath after the war against the dragons had ended and the Witch of Izalith used the power of flame during the war, they are likely unrelated.
  • Discovering that this is not the case is a major revelation of the later story arcs of Destiny 2, with Light and Darkness revealed to be complementary forces rather than opposing ones. First Guardians empowered by the Light start gaining Darkness-based abilities, then the Hive who are empowered by the Darkness gain the ability to use the Light.
  • Dragon Age specializations for mage characters effectively work like this from the second game onward.
  • Averted in some Dragon Quest games where the Job System lets you keep magic learned in one job when switching, allowing for some stupidly powerful parties (imagine four examples of The Berserker fully healing himself whenever he feels like it). Eventually enforced in VII when it got a remake, as the Prestige Class spells were made mutually exclusive in order to avoid A) the "stupidly powerful" issue and B) having the entire party play the exact same way (the less-game-breaking basic class spells were allowed to continue carrying over).
  • Many Final Fantasy games that have job classes normally have classes that are only able to use one magic type, such as black mages and white mages using Black and White Magic, respectively. This gets muddled, however, in games like Final Fantasy V, Final Fantasy Tactics, and Final Fantasy XI that allow you to use secondary abilities from a class you've previously worked on. It should be noted, of course, that games like Final Fantasy XII throw all this out the window and give everyone the potential to learn anything, certain attacks aside.
  • Most Fire Emblem games don't have any classes that can learn both light and dark magic, and only exalted classes can cast any two between light, dark, and anima.
  • In Jade Empire, you must choose between Fortune's Favorite and Golden Star, and Ice Shards and Dire Flame in Act I, but can buy the other later. In Act II, however, you can get Stone Immortal if you are far enough on the Open Palm end of the spectrum and Tempest if you are far enough on the Closed Fist, and have no opportunity to get the other.
  • Variation in Knights of the Old Republic. Jedi can use Sith powers, and vice-versa, but suffer a penalty to the spell cost (and likewise a bonus to more properly aligned force powers). They're not completely exclusive, just more costly.
  • In Mabinogi Fantasy Life, the Dark Knight transformation is incompatible with the Paladin transformation. However, there is also a story-reason for this as well as magical incompatibility: the choice one makes to become a Dark Knight would make one unable to access the Paladin transformation anyway.
  • In Majesty you can build temples to seven different gods, but certain temples cant be built if there's a conflicting temple already in your settlement. You can have a temple to Lunard (moon), or a temple to Helia (sun). You can have temples to Krypta (death) and Fervus (chaos) or temples to Agrela (life) and Dauros (law). Or you can build a temple to Krolm and not have any other temples. Since each temple gives you specific kinds magic you are thus forced to chose which mutually exclusive spells you want.
  • In Master of Magic you cannot learn spells from both the Life and Death magic schools. All the others can be combined, (and these two can be combined with any of the other three schools) but not these two.
  • Meridian 59, the first "3-D" MMORPG, allowed you to master only one type of magic at a time. You could become somewhat decent at another one. But mastering another type meant you became less powerful in the other.
  • In Might and Magic VII, learning Light and Dark Magic is mutually exclusive under the 'teachers don't get along' rule (even the Basic teachers refuse to teach you how to use the school unless you align with the Path of Light or Path of Dark. Since that is a mutually exclusive choice made during the main questline...). VIII has it be mutually exclusive by having the classes that can learn them be specialists in one or the other (the Clerics are — potentially disloyal, but still — members of the Church of the Sun, a religion associated with Light Magic, while Sorcerers are replaced with Necromancers — who focus on Dark Magic since that's the school involving raising the dead as undead to serve you), though you can at least have them in the same party, unlike in VII. The game that introduced them (VI), however, makes clear that there is nothing inherently mutually exclusive about them, and indeed if you are eligible to learn one you can learn the other as well there (mastering both takes a great deal of effort, but that is because the Master teachers demand that your party has a really good or a really bad reputation, respectively).
  • A downplayed example in the Persona series. Personas cannot inherit skills opposite their affinity from fusion (for example, an Ice-elemental Jack Frost cannot inherit Agi/fire spells), though one may use a skill card to get past this restriction.
  • In Quest for Glory V, a Hero with magic abilities can either get the First Aid spell for healing or Dragon Fire spell for offense. It all depends on who you save from Hades, Erana or Katrina respectively.
  • In RuneScape, there are four different spellbooks: the ancient spellbook has offensive magic, the lunar spellbook has skill-related spells, and the normal spellbook has a mixture of both. The last one, the Arceuus spellbook, is unique in that it deals with putting souls to rest (communicated in-game with ensouled monster heads) and has teleports to places connected to death. It is only possible to use one magic from one spellbook at a time. However, players can switch between spellbooks at certain fixed places, including your player-owned home if you have enough experience in Construction and money.
  • This has been a staple of the SaGa series since the Romancing SaGa Trilogy: you can only learn only half the magic spells. In Romancing SaGa 2, however, you can combine specific elements if they are not opposite to each other to create new and more powerful spells.
    • In SaGa Frontier, one can master Light OR Shadow magic, Arcane OR Rune, Time OR Space, Realm OR Mystic, and Mind OR Evil. If you buy magic in an opposing school, you'll forget all the spells you knew. The Magic Kingdom finds away around this by developing artificially created twins, two of which are Blue and Rouge. In Blue's story, one gains his brother's magic after the Wizard Duel between them, creating one magician with all the magic. This is a gambit by the Magic Kingdom to create someone capable of defeating the Lord of Hell in his own region.
  • In early Shin Megami Tensei games, the hero is the only one who can use demon summoning magic, but are often the only party member that can't cast other spells.
  • in Spider-Man: Shattered Dimensions, it's the reason that our hero can defeat The Juggernaut in a fistfight. Normally, the Juggernaut is impervious to physical harm, however, he ends up coming into contact with a magical tablet fragment that interferes with his normal source of power, the Ruby of Cyttorak.
  • Starcraft: Protoss have the high templar ("light") and the dark templar, separated for hundreds of years before the start of the game. One of the main heroes eventually learns to use both types of power and use it to defeat the Big Bad (the first one, anyway). It's insinuated that only an extremely exceptional individual is able to pull this off. There are at least two recorded individuals who did so, but both died shortly afterwards (Adun burned himself out, Tassadar crashed his ship into the Overmind in a Heroic Sacrifice).
  • In Suikoden Tactics, mages have an inherent element (Water, Lightning, Earth, Wind, Fire) and these elements are arranged in a ring where each one is strong to the one preceding it and weak to the one after it. Mages cannot use magic of the element that their inherent element is weak to.
  • Unreal Tournament has a mod/gametype called U 4 E Fortress. One of the classes in this mod is the Wizard, which unlike the other classes can level up and gain spells from eight different schools (think Constant Warriors Linear Wizards). When the Wizard first learns a spell from a school, a selection of other schools becomes Lost Forever. However, some servers allow all spell schools after a certain level.
  • In the Warcraft universe, most Priests cannot use both Holy and Shadow spells, though Discipline Priests have recently learned how to combine the schools of magic without going insane.
    • Most Warrior abilities require a certain stance to use, meaning that while they can use abilities more in tune with their other specializations, they would have to switch to use it, which prevents them from using the abilities most vital to their role until they switch back.
    • The Expanded Universe (most notably Rise of the Horde) depicts Fel magic as the antithesis to other magics. Orc shamans who learned Warlock magic found the Spirits no longer responded to their calls. This then extended to other shamans who never touched Fel magic, their race was so corrupted by then they were completely incapable of using anything else. They got better. Blood Elves were originally shown stealing their Light magic from a captured Naaru because their demonic taint wouldn't let them harness it legitimately until the Sunwell was restored.

    Visual Novels 
  • The Nasuverse:
    • Magic and powers from Gaia counteracting each other. Humans are cut off from Gaia specifically because of their development of Magic Circuits. Arcueid from Tsukihime uses her Marble Phantasm to create even more powerful effects than magic can, but is highly dependent on her surroundings and is also limited to effects that can happen in nature. You simply can't use both systems. However, the Church's divine powers do work with magic and are partially based on it.
    • Eastern and western styles of magic are considered incompatible with one another (for starters, Continental Asian Magecraft uses a completely different system of accessing spell formulas via Philosophy Foundation that Westerners don't use) so mages of either style tend to keep to themselves. The only reason mages from the Clock Tower even consider coming over to Fuyuki, Japan in the Fate Series, which is otherwise considered the magical boonies for them, is because it was the chosen place for the Holy Grail War.

  • Stand Still, Stay Silent: According to Word of God, the Norse gods won't choose Finns as mages and Finnish blood is required to have a chance to be a Finnish mage, which means people can't be both.

    Western Animation 
  • Mixing different schools of magic in Aladdin is highly dangerous. This was frequently used, besides his diminished power, to keep Genie from being able to fix things too easily.
  • In Avatar: The Last Airbender franchise, the ability to bend one of the four elements (water, fire, earth, and air) is mutually exclusive. Mixed-heritage people take after one side or the other (or possibly neither). That is not to say that studying other disciplines is pointless, as you can gain tremendous insight into how Bending works and come up with new techniques. Iroh, a firebender, developed lightning redirection by observing waterbenders. The one exception to this rule is the Avatar, who is able (and required) to master all four elements. Even then, there's a spiritual or philosophical divide between the techniques used for each element — Aang was raised an airbender, which is all about flowing with the surroundings, and had trouble with the stubborn assertiveness that earthbending required. In contrast, Korra is brash and hotheaded and has serious problems grasping airbending due to its go-with-the-flow philosophy being so opposed to her own temperament.
    The mutual exclusiveness is elaborated on in The Legend of Korra when we find out about the origins of Bending. It was originally a power bestowed by Lion Turtles, but a human physically could not contain more than one power at the same time. If a person wants to bend another element, he or she must give up the previous power. The first Avatar got around the limitation by gaining the help of an extremely powerful (if weakened) spirit, eventually merging with it.
  • Hilda: In The Movie, this is the reason why Frida, who is a witch in training, cannot use her magic to restore Hilda back into a human after she became the victim of a troll changeling spell; witch magic and troll magic don't mix and cannot be used to counter each other.
  • Invoked in The Owl House. All witches are required to join a coven upon reaching adulthood and recieve a special tattoo that prevents them from using any spells outside of that coven's target of study aside from the most basic ones. The only ones who have no limitations are those lucky few within the Emperor's Coven (plus covenless witches like Eda, but they are hunted down as criminals).
  • In Teen Titans when Larry breaks his finger that lets him rewrite the rules of reality, Raven says she can't use her magic to heal it since combining their two powers could create an Earth-Shattering Kaboom.