Follow TV Tropes


So You Want To / Write a Functional Magic System

Go To

Magic is a tricky beast (Ha!). While it certainly adds a gleam and sense of wonder to your work, it can easily get out of hand. Make it too powerful and it can become a "Why Don't You Just Shoot Him?" story with everybody carrying an Idiot Ball. Make it too weak, and it's like it's not there at all.

The simplest (but nobody said "easiest") way to solve this problem is creating a magic system: that is, a set of laws and rules that your magic users must abide by. Let us go, step by step, through the process of inventing a magic system.

Where Does Your Magic Come From?

Magic is a lot like religious dogma. It has its origins, its laws, its rites, and a badass prize if you fulfill all requirements. The first of those is especially important.

Where your magic comes from defines how your magic users (let's call them mages, for sake of simplicity) use it. You have a few options:

  • Magic Comes From God(s): All spells are actually rites and prayers to the god or gods that actually use said power on the mage's behalf (or perhaps while the mage can use magic, it doesn't naturally regenerate in mortals, so they must ask the gods to replenish their supply). There can be many gods, so you have to decide whether the mage is devoted to one deity or if they can call on any gods they wish. Gods can have their tempers and problems; they may not always do what the mage asks them to, or they might be unable to meet their demands. Maybe the mage has annoyed the god for some reason, so now the deity will withdraw their power from the mage. Maybe there are areas that are outside of the deity's jurisdiction (No Thor mages in Hel's temple? Demonic magic doesn't work in churches? You decide!).
  • Magic Is Life Energy: In this case, the mage does magic using the energy of living beings. This brings up interesting questions: does your "life magic" protect you from the magic of others? This could mean that mages can't attack other living beings directly. Can the mage use the magic of others, or are they limited to what their own body can keep? Watch out — if a mage can suck magic out of nearby living creatures, the Power Perversion Potential is beyond belief. Can you run out of life energy for your magic? This is the most obvious limiting factor. Does "no life energy" mean death? This is not so obvious. On one side you have The Parasol Protectorate, where not having a soul means you have very powerful magical skill, and on the other there's (among others) the Inheritance Cycle where no life energy is literal and means instant death. Which side you are on is your choice.
  • Magic Is Energy That's Everywhere: Or The Force Option. Magic is some sort of supernatural power that flows everywhere and connects everything. In this setting, a mage is a person that can manipulate magic, but here lies a pitfall: you have to limit the range of a mage's powers in some fashion. After all, wouldn't the plot of Star Wars be kind of senseless if Darth Vader could just explode the Rebels' brains on Hoth?
  • Magic Is the Energy of a Parallel World: In this approach, magic is energy in some sort of subspace and the mage acts as a kind of interdimensional conduit, letting magic flow through them into our world. Of course, this brings up yet another set of interesting questions. Where does this magic come from? What effect does magic have on the mage who channels it? Is there a limit on how much magic a mage can let through? Does the flow of magic damage the mage in any way? Can the flow of magic be controlled? Can things act as focuses for magic, like some sort of symbols? Does it matter where the mage is when they start channeling magic? Can magic be tainted in some places and purer in others?

Of course, nobody forbids you to mix the above. Maybe in your magic system, deities enable mages to channel the magic from the realm of the gods. Or maybe wild magic is everywhere and life magic can be used to harness it. The choice is yours and — of course — feel free to invent new origins.

Who Can Do Your Magic?

We're using the word "mage" here, but then, who can be the mage?

  • The Chosen Ones: A very elite group. Maybe it's one/few in a generation. Maybe one/few in their time. Definitely a very small, tiny group. This means a lot: if there's only one in a generation, then the only person who can teach magic is somebody from the previous generation, meaning that a teacher has to be found. If there's only one in their time (like Jenny Sparks from The Authority), then they must home school. Of course, if there's no antagonist, there's hardly any story, so it's nice to have at least two in a generation/their times. And if you make it more, you can craft a nice Five-Man Band. But preserve the feeling of extreme uniqueness of the magical gift.
  • Supernatural Entities: While the Chosen Ones are humans, Supernatural Entities are anything but. This is also a very elite group, but they are inhuman in origin, amazingly powerful, superior to people, and possess wisdom beyond the mortal kind (they might be immortal, of course). Think of wizards in The Lord of the Rings, who were the angels of the setting. Of course, this works better when magic comes from (a) god, but you can as well make them Starfish Aliens. They make poor protagonists, though, mostly because they know too much and are too powerful.
  • Mage Subspecies: Probably the most common variation. There is a group of people that can do magic. This may be 1% of the population or less (but be careful with percents — 1% of Earth's population is 70 million people!), but may be more. In this case magic is hereditary (like in Harry Potter — you can put some magical genetics in here).
  • Spontaneously Magical: This often overlaps with Mage Subspecies and competes to be the most common variation. Basically, some part of population (again, if you want the masquerade, keep it below 0.01%) spontaneously exhibits ability to do magic. Once it appears, it's often hereditary, turning this into Mage Subspecies.
  • Students of Magic: Magic is a skill that can be learned after years of study and/or a pact with some supernatural being (gods, demons, whatever-they-are-in-your-setting). How popular your magic is depends on how hard to learn you'll make it. If it's super hard, it can overlap with Chosen Ones in frequency. If it's so easy preschoolers start to learn it, it may overlap with points below.
  • Nonhumans: Simply put, if your setting has nonhumans, only they can do magic. Traditional (somewhat cliche) differentiation here is elves=mages, humans=warriors and dwarves=makers, but you can mess it up anyhow you wish. If nonhumans look like humans, you have to decide whether or not half-nonhumans exist. Would they have magic too? And, of course, most of the above points can apply to nonhumans. Mage Subspecies of elves? The Chosen Ones among dwarves?
  • Everybody: Basically, magic is an omnipresent skill and everybody is born with it (think of Codex Alera, where everybody in every race has magic). Can and usually will overlap with Students of Magic, the super-easy variety.

Check out Our Mages Are Different for more ideas.

How Is Your Magic Done?

Ah, the very core of it. You have your source, you have your mage and now you want them to do something awesome. How does that happen?

  • Nervous System Triggered: The mage creates magical effects by just doing it, in the same way we do things like moving our arms or talking. This works for genetic mage types shown above like Mage Subspecies, but makes little sense with non-genetic ones like Students of Magic, so be careful if you use this.
  • An Effort of Will: Basically, the mage wishes for something very hard. Effort of will should probably require focus (How strong? Your choice.), and what happens if this focus is broken? It probably gets easier with practice (most things do). Or maybe it's so easy the mage barely has to focus at all? That presents an entire new range of problems.
  • Hand Gestures: Specific gestures result in specific magical effects. This may be accompanied by effort of will, but if it's not, let's consider the implications: If waving resulted in setting what you're looking at on fire, how would you signal things to people far away?
  • Seeking the Inner Magic: There is a place "inside" the mage (either body or mind) that the mage has to reach for and grab the magic to make it do something. It usually accompanies other points on this list, but doesn't have to, like in Mistborn, where simply grabbing one type of metal from a mage's inside made magic happen.
  • Giving Orders to Magic: The mage has to say what they want to happen. Maybe it has to be said clearly, maybe in the language of magic, but the thing is, it has to be said. Probably a nice idea is to have this accompanied by effort of will. Also consider what happens if the magic misunderstands the mage's request. Prayer is another variation on this.
  • Magic Spells: Classic among classics. Nonsensical (or maybe it makes sense... somehow?) string of letters, maybe something the mage makes up to give "base" to their effort of will (a la The Dresden Files), maybe a combination of sounds that "unlocks" magic. Either way, it's a sound to be spoken.
  • Signs: Another classic, probably Older Than Dirt. Lines, shapes or their combinations act here as keys, allowing magic through (or maybe making it?) and shaping it to fulfill a specific purpose. Signs can come in many varieties — drawn on dirt, painted, written, carved, forged, tattooed...
  • Things: Magical pieces of equipment that either let magic through or radiate it. Crystal balls, Dragon Balls, wands, MacGuffins, staffs, beautifully detailed pieces of machinery, Green Rocks... It can be practically anything.
  • Magic Circles: Not necessarily circles, although they are most popular. Geometrical shapes drawn on surfaces (or maybe in the air if that's possible in your setting), with magic happening inside.
  • Rituals: This is used rarely. Rituals are sets of actions accompanied by pieces of equipment. This is very impractical and we suggest to reserve it for big spells (two-hours-long dance and candles placed around triangles filled with the blood of a freshly-slain pig to... light a candle? Kind of lame, especially if you have matchsticks in the setting).

Of course, most settings mix many of the above and some just go with all of them.

What Can't Your Magic Do?

Now, we don't want to spoil the fun, but there must be the line you just don't cross. Making your magic omnipotent kills every plot you might imagine (apart from "entity that makes magic happen was kidnapped"... but if magic is omnipotent, how come the entity didn't free itself already?). Therefore there must be limiting factors to your magic. You can invent some brilliant One Rule that covers all you (and the reader) can think about, or you can go with multiple limiting factors. However, they must follow the rule of two Rs: limiting factors must be Reasonable and Respected.

  • Reasonable means that they are logical consequences of nature and of the mechanisms of your magic. Weaksauce Weakness is unadvised — it would be kind of ridiculous in a magic-is-everywhere setting if goblins couldn't enter coffee shops because coffee is their only weakness. It would, however, make sense in a magic-comes-from-gods setting if goblins couldn't enter coffee shops because the god Cafe (patron of coffee) hates Gobli (protector of goblins) and kills every goblin that enters his domain. Or, in a magic-is-life-force/magic-is-in-subspace setting, if goblins need magic to live, coffee may block their biological connectors with magic, set in their throats.
  • Respected means that everyone must abide by the limiting factors. You can't state at the beginning of your story that water mages can't use fire and then, in the climax, have a water mage throw fireballs. This encompasses everybody — gods don't get a free pass either, unless you design an entire different (looser) set of rules for them.

Some sets of limiting factors are more popular than others. Among them are:

  • Limitations of Body (and Soul): Your body can stand only this much magic flowing through it. Or doing magic is as tiring as physical exercise (this suggest that the stronger physically you are, the more magic you can do). Or it requires so much focus, you can't keep it up for too long. Anyway, this is the most common factor.
  • Finite Amount of Magic Available: At the moment, the universe can offer you only this much. Or maybe the local place was drained of magic long ago. Or maybe you have to share with other mages in the area, or your body houses a finite amount of power. Anyway, it's not enough for more complicated issues.
  • Geometric Growth of Complexity: The more powerful the magic you want to do, the more complicated it is, and the more measures are needed to make it happen. Maybe you could raise the mountain from the ground, but it requires a seven-book-long spell to be sung in baritone under the moonlight. While standing on your hands.
  • Exotic Materials Necessary: Popular in games. The more powerful the spell, the rarer and more expensive the necessary substances are. The most powerful spells require the rarest substances, maybe even legendary ones. Want to raise that mountain? Do you have seventy kilos of platinum and two tons of dysprosium?
  • All You Can Sense: You can manipulate only what you can feel with one of your senses: see, hear, touch... Sight is the most common option, but remember that there are five senses. What if magic only works on something you can taste?
  • Range of Magic: You have your range and magic works only inside it. Range can vary: it can be only what you touch, everything in the sphere of twice-your-height radius or maybe everything in your line of sight? Be careful with the first and the last one. If you touch the ground, can you manipulate the entire Earth? If you see somebody on a TV screen, does it count as your line of sight?
  • The Higher Powers Won't Let You: There is some greater god/deity/entity that doesn't want you to use too much power (Why? Dunno. Maybe they're a jerk, or maybe they're fending off hordes of abominations and needs that power). It will simply block you. Or maybe two competing entities are blocking each other, so that none has enough power.
  • Nothing Appears From Thin Air: This means that you can manipulate things that already exist (set them on fire, move them, explode them), but you can't conjure anything that isn't here or turn one thing into another (turn iron into gold, make a wall of bricks appear). Remember, though, that turning water into ice is not turning one thing into another. It's the process called freezing.
  • Your Magic Ends Where My Magic Starts: Popular within magic-is-life-energy settings. The magic of one person blocks the magic of another. Therefore, if every living thing has magic, you can't magically interact with them.
  • We Don't Know Everything: If your magic is based on symbols or spells, you can't reasonably expect mages to ever discover all combinations. It's mostly trial and error and you never know what just won't work and what will explode in your face. Maybe there is a spell that raises a mountain, but mages are running out of ideas of what could it be. Of course, this works less when your magic is based on effort of will or giving orders to magic.
  • Regional Lockout: Use of magic is restricted to certain places only, and it either works very poorly or straight out refuses to outside them. This can happen due to a variety of reasons, that are either inherently connected to its nature, or caused by outside sources. In cases of elemental magic, it may be tied to the "dominant" element in the environment — a water mage might be useless in the middle of the desert where a fire mage's powers are at its height, but at sea the roles are reversed. With nonhumans, magic could only work in their natural habitat — elven magic doesn't work outside of their Hidden Elf Village (even more so if Magic Comes from Gods comes into play). Outside factors usually include magic coming into conflict with another force: Magic Versus Science may be in play, and any usage of supernatural powers near advanced devices is doomed to fail. Or the resident Anti-Magical Faction may have found a way (maybe with help from some divine power, especially if they're of the Knight Templar variety) to prevent magic from working in the lands they control. Of course, you can just arbitrarily decide that in some places magic just doesn't work, period — but what's the fun in that?
  • There's a Counter for Everything: The rational conclusion of magic being an integral part of the world, and a popular form of magical arms races — everything it can do can be undone as easily, and someone probably already thought of that. In other words, for every Fantastic Nuke out there, there is probably a magic anti-missile ready to shoot it down mid-air. You want to teleport right into Emperor Evulz's fortress? Have fun being tele-fragged by his anti-teleportation fields. Magic flyers probably have to worry about some spell-powered AA batteries on the ground, and important places may employ checks for disguised polymorphs. Unlike other options described above, there is no "hard" limit on what magic can do. Since no countermeasure is 100% effective, heroes (or bad guys) can temporarily circumvent them: anti-teleportation fields can be scrambled, there might be a way to pass the checks, and a particularly skilled mage can avoid fire in a display or magical dogfight. Just make sure events like that are rare — after all, if something failed most of the time, there is no reason people will continue to use it.


  • Be sure you have all bases covered. For example, if the rule states that mages can't manipulate living beings, some might start to ask you what about animating the dead? Or manipulating skin, since the upper layer is dead tissue?
  • Take your rules to their logical conclusion. If your setting has water mages, remember that the human body is over 70% water. If you can heal wounds by touching somebody, remember that doctors can kill with the same tools they heal with. If you have elemental magic, don't forget that weather is a relation of air pressure and water, therefore your powerful air/water mage can control weather, too. If invisibility works for your clothes, does it work for the mobile phone you keep in your pocket, or wall you touch with your hands?
  • Be careful with the "line of sight" rule. As was mentioned before, "line of sight" is one thing if you're in a closed room, and another if this closed room is a security center with a dozen camera screens. Can you manipulate something you can see through Skype? Standing on a mountain peak, can you manipulate everything you see from there? Can you manipulate the sun if you look at it? Stars? Can a blind person use magic?
  • Avoid Deus ex Machina and New Powers as the Plot Demands. If your adventuring party of water mages must beat Evil Lord Evulz, whose only weakness is sunlight, don't give one of them sunlight manipulation powers all of a sudden. This raises two questions: how is this possible in your setting? And if this is possible, why couldn't the hero get this skill at the beginning of their adventure?
  • Try to make your magic abide by the rules of physics (or at least logic) as much as possible. If something burns, it should burn out. Fire can burn only when it has air, heat and fuel. Convection, Schmonvection is terribly unrealistic. Pressurized air should cause a small explosion when pressurizing forces stop working. "Disappearing" something should cause implosion. Applying too much electricity should burn electronic equipment. Think about what consequences your magic would have and try to keep the rules of preservation of mass and energy.
  • Be sure you know what you're writing about. While writing about elemental magic, you can of course go with traditional fire-earth-water-air-electricity-whatever, but don't forget that both fire and electricity are processes, not things. Also, remember that ice and water are the same things and define whether by air you mean all the gases, or only oxygen and nitrogen. If your life magic can't touch the magic of other living beings, remember that air all around us is crammed with bacteria and other microorganisms, which are alive.
  • Once you set the rules, don't change them. Of course, you can invent the rules as you write the story, but once you set a rule, it's a canon. You can't break your own canon, because that makes you an unreliable writer and opens unhappy possibilities of New Powers as the Plot Demands in the minds of your readers/viewers.
  • Don't put too many limits on your magic. All the above are nice and realistic, but remember, you introduce Functional Magic to use it, and the entire charm of magic is that you can make really awesome things with it. Make your rules few, logical, and easy to remember, and don't let them limit you too much.

Writing Tips

Of course, you're the creator, so magic in your universe is yet another tool you can use to write interesting stories. Some possibilities are:

  • The very nature of magic can become the basis of your story. Read "The Chosen Ones" point. This is a plot ready to be written!
  • Tell your readers what the rules of your magic are, or at least explain the basics. Some predictability is nice to have, and it cuts off any speculation along the lines of but why can't they...
  • Having a mage as a protagonist helps you explain the rules, but it's not necessary.
  • Put a newcomer into your story, to whom other characters may act as Mr. Exposition, explaining magic. Dialogue is always more interesting than long Infodumps. Otherwise, feed your readers/viewer one bit of information at a time so that they won't feel buried under tons of data to process.
  • Note that you don't have to tell anyone what the origin of your magic is. Readers/viewers don't have to know it — but you must.
  • Of course, you can be devious! Tell your characters (and readers) about one possible origin and working set of rules... and then dramatically reveal that this is only part of the truth and expanded rules and origin means you can do much more!
  • Remember to keep Sanderson's Three Laws in mind.

Whatever you chose, remember — readers are not the only people here who can have fun!

The Greats

  • Brandon Sanderson is often regared as the king of this trope by large parts of the online community, and for a reason — his Realmatic Theory of Investiture that govers all magic of The Cosmere is as rigid as the laws of physics. A good example of it would be Allomancy in Mistborn:
    • The system is powered by the magic of the god Preservation, which a mage, called an allomancer, can channel by "burning" various metals in their stomach. You can be an allomancer of one power, or of all of them; nothing in-between.
    • There are sixteen allomantically-active metals, and each metal bestows only one power; no variations. An alloy of a metal bestows power opposite to the pure metal — for example, iron lets you pull metallic objects to you, while steel lets you push metallic objects away from you.
    • An allomancer is limited to the amount of metal in his or her body at the moment; the metal can be burned faster and thus produce stronger effects, but it will burn out quicker; likewise, it can be burned more slowly and thus take longer to run out, but the effect will be weaker.
    • Rules of physics still apply; if you try to use steel to push on something heavier than you, you will be pushed away; likewise with iron-pulls.
  • For all its flaws, the Inheritance Cycle's magic system is simple, but sound.
    • Magic works by voice commands given in Elven language, accompanied by some amount of effort of will; an extremely practiced mage may forgo spoken command and only focus on effort of will, but this has high chances of backfiring or not working in the intended way.
    • Magic is very literal in its interpretation of spoken word; therefore one must be careful when forming a command. When Eragon blesses a girl with magic, a grammar error turns a desire to be shielded from misfortune into her **becoming** a shield from misfortune, making her feel a literal compulsion to aid those in need. Likewise, you have to know something's precise name in Elven to attempt controlling it; hence the series' infatuation with true names of people.
    • Magic is powered by energy of the caster, though surrounding sources of life can also be used; the amount of energy used for a spell is equivalent to how much would be used to perform magical action manually. You can order magic to raise an especially-heavy boulder, but it would quite likely kill you from overexertion, unless you outsource it to some nearby plants and animals and don't mind them dying.
  • Though it doesn't originate from literature, the system in Magic: The Gathering has many worthwhile lessons, particularly as it was a partial inspiration for Sanderson's Three Laws. Spells in Magic are divided into five colors. Each color represents a different philosophy or ideology, stemming from a virtue but taken to such excess that it becomes the color's Achilles' Heel. For every thing a color is good at, there's typically at least two other things it's not good at, a Competitive Balance that encourages Tactical Rock–Paper–Scissors.