by Janet Forbes
“If you strike me down, I shall become more powerful than you can possibly imagine,” says Obi Wan Kenobi.
It’s a really cool line. But as someone who writes Science Fiction and Fantasy, a little bell goes off in my head. How powerful? Powerful enough to do ANYTHING?
Because that’s a one-way ticket to a broken story. Overpowered items, superpowers that are just too super, or get-out-of-jail-free technology are easy to create by accident. And suddenly, your main characters have a “Travel-Sized Miracle Device” to solve every problem you throw at them. It’s a conflict killer.
And its not just SFF writers who have to deal with this. Even an everyday cell phone can mess up your story, and give your characters too many options.
When characters are TOO powerful, it’s hard to explain why they fail. But try-fail cycles are critical for story advancement, for keeping the Mary-Sue out of your dramatis personae, and for keeping characters active and stories interesting.
Enter - the Triangle of Power.
No, it’s not some arcane casting ritual: it’s a tool you can use to balance your worldbuilding, stop abilities becoming too overpowered, and improve your narratives.
What is the Triangle of Power in worldbuilding?
The Triangle of Power is my model to prevent magic and technology (and other abilities) from unbalancing your worldbuilding and throwing off your story. It consists of three “levers” you can adjust - Abilities, Cost, and Limitations. And for us, as writers and storytellers, these levers don’t just balance our worldbuilding and save our plots: they have SERIOUS storytelling potential too, if we use them right.
And it’s not just for crazy magic and far-future technologies: everyday technology like cell phones ALSO obey the Triangle of Power, and work better in stories because of it.

Abilities - what does it do?
It’s often easiest to first describe the core Ability. What does the magic, the technology, the psionics or superpower, do? What effect does it have? What change does it make to the world? Or what information does it reveals? For example:
- A cellphone lets you call someone, look things up, has a flashlight, maps and more
- The One Ring turns the wearer invisible
- The WARP drive allows the Starship Enterprise to travel faster than light
- The D&D spell “Zone of Truth” creates a 15 foot sphere in which everyone must tell the truth
- Superman is a veritable Swiss Army knife of special abilities: flying, cold breath, laser vision and more!
Sometimes abilities are more nebulous than these examples. And that’s OK too. For example, I was helping a writer with their fairy magic system in which pretty much anything is possible. In fact, that’s where costs and limitations become SUPER important. Because when anything is possible, it actually becomes harder to write the story, or explain why a character can’t just magic their way out of a problem.
Traditionally, Abilities are the shiny thing that people remember - it’s the side of the triangle that takes most of the focus. But it’s the one I’ll spend the least time on here because, in many ways, it’s actually the simplest. And funnily enough, although it seems the most exciting, it actually has less storytelling potential than the other two sides.
Cost: what does it take?
The next side of the triangle is Cost. What kind of input is needed for the Ability to happen?
Going back to our previous examples, here are some costs of well-known abilities:
- A cellphone needs battery and payment to a network to keep it working
- Wearing the One Ring erodes your soul (creepy!) and also reveals your location to Sauron
- Star Trek’s Warp drives require “fuel” to run it.
- The D&D spell “Zone of Truth” requires a spell slot. Some D&D spells also require material spell ingredients
- Superman needs radiation from our red sun in order for his super powers to work. Otherwise, he’s just Clark Kent in spandex and external underwear.
Costs might be dramatic and visceral - your soul (or someone else’s soul, like The Elder Scrolls soul gems), your blood, a heart or another body part (yours or someone else’s). They could be something less tangible, like energy, life force. The cost might be something that regenerates over time, like mana, spell slots, or stamina (after a good long lie in, you’ll be ready to cast spells again!) But it could also be something finite - like an item that disintegrates once its magic “charge” is used up.
Even a simple cost has story potential - how often did the Star Ship Voyager stall because they were out of deuterium, or have to engage in dodgy dealings to resupply? Or how about the archetypal villain, harvesting souls to power a doomsday device? Passive characters can be the death of a story, and seeking out the costs needed for an ability is a great way to compel your protagonists and antagonists into action! Whether they have to buy, steal, mine, retrieve, or negotiate for it, a cost can inject action into your story.
But costs can also create really interesting character moments. A cost could be “consequences”. For example what if, as you heal this person in front of you, you’re stealing the life force from someone else? What does it say about the character who uses this magic?
Or perhaps you’re desperate enough to steal luck from tomorrow so you can win at cards? Just know that you’ll be banging into coffee tables and dropping your toast butter-side-down for the rest of the week.
And a cost may not be immediately obvious to a character. Having them slowly realise the cost of an ability as the story progresses has great character development potential. As a bonus, it’s a great way to pace the learning curve of your worldbuilding exposition.
Limitations: What It Can’t Do?
Kryptonite was first introduced to comic mythos because Superman's invulnerability was considered "boring". And that’s exactly why you need Limitations.
In the Triangle of Power, Limitations are…. the other stuff. In D&D these are common: something only works within 30 feet, or can be blocked by a dead magic zone. In science fiction, limitations are important too: a dust storm or radiation can block your radars or clog your engines. A piece of tech might only work in earth-like gravity, or a spell might only work during a planetary alignment.
You’ll notice that Limitations are different from Costs. Cost is like an input - souls, mana, blood, spell-slots. Limitations are more like conditions that must either be met (like special circumstances) or must be avoided, like “interference”.
Going back to our previous examples, here are some Limitations of those well known examples:
- A cellphone can’t work underground, or where there’s no cell service. It’s susceptible to getting wet and can also be damaged fairly easily
- Everything from subspace interference to ion storms disrupts Star Trek’s Warp drive
- The D&D spell “Zone of Truth” takes a few seconds to cast (it doesn’t happen instantly) and only lasts 10 mins. It has range limitations, and not everyone can cast it - only powerful enough magic users of the right class.
- The One Ring has one of the most interesting limitations - it makes its own decisions about who it wants to carry it. To quote Gandalf: “It was not Gollum, Frodo, but the Ring itself that decided things. The Ring left him.” (from Fellowship of the Ring).
- The presence of Kryptonite, in its various hues, can remove Superman’s powers, memory or his inhibitions
Limitations can include “nerf” zones, like dead magic zones or specific environmental conditions, like gravity, temperature or altitude. Bloodlines - or being the chosen one - is a common limitation for magic users. Limitations can be duration specific - an item might only work for a certain amount of time before overheating - or time specific (a magic that only works at night, for example).
So why bother introducing Limitations to the Triangle of Power? Well, limitations force characters to try something new, even when they’ve already got their hands on the ALL POWERFUL ARTIFACT. This guards against your characters repeating the same actions, and using the same Ability (read: magic or tech) to solve every problem. It makes them get creative, which makes for more interesting stories!
Of course, you have to be careful. Using the same limitation too often can feel cliche, like the old “cell phone with no signal”. But, having your characters bump up against limitations can be a powerful start to a try-fail cycle.
Theme and Balance in the Triangle of Power
So ability, cost, limitations are the fundamental building blocks of your magic items, spells, powers and technology. But there’s one more thing: your ingredients have to work together.
To start with, your ingredients - that is, the sides of your triangle - should be about the same “size”. If the item with WORLD ENDING POWER only demands a drop of blood as a cost, and has no meaningful limitations, then it’s going to be pretty world breaking. Literally anyone who gets their mitts on is going to derail your story pretty quickly. Apocalypses everywhere.
But if your ABILITY is to Summon Cthulhu (a pretty mighty worldending power), then a good COST should also be hefty - maybe the immortal soul of an angel, something significant and difficult to source. And the LIMITATION might be something just as rare, like “when the planets align” (it’s a classic for a reason, just sayin’).
And if your ability is something small, like “manifest a single drop of holy water,” then the costs and limitations should be small - or no one will use it! For example, one drop of holy water (power) costs a single drop of blood, and you can do it once an hour - that’s the only limitation. It’s a small power, with small costs and limitations.
For more advanced worldbuilders there are ways around a totally equal Triangle of Power: like doubling limitations and removing costs. You can also tweak the weight of costs and limitations to make magic easier or harder in your world. Low magic worlds might have extreme costs and limitations, which only the desperate would bother negotiating. And that brings me to mood and theme.
Because, as with everything else in worldbuilding, it’s important that your Triangle of Power fits your story’s mood and themes. That’s critical for creating the atmosphere you want, and making it feel real and connected.
If your magic’s cost is the blood of a hundred virgins, but your power is bringing back the marshmallow fairies, then you need to take a long, hard look at your worldbuilding. This item is balanced, but it’s still broken – it betrays the spirit of whatever you’re trying to tell the audience. That is, unless your marshmallow fairies are really freaking scary. In which case, keep them away from me.
Keep things balanced and themed, and your abilities will be as memorable as the One Ring, the Warp Drive, an iconic D&D spell or even Superman.
As always with Worldbuilding - write it down!
Even the best ideas get forgotten! If you’ve gone to the trouble of creating awesome Abilities, fascinating Costs and rich, world-based Limitations, make sure you keep a note of them, and link them to the people, places and things in your world. A worldbuilding software like World Anvil is the perfect place to keep them, and it integrates seamlessly with manuscripts, the novel writing software!
I really hope the Triangle of Power inspires you to create - and balance - some fascinating new things in your world. If you want more, I’ve created a Triangle of Power video with more examples.
Do you already use costs and limitations in your stories? How have they helped… and have they ever gotten in your way?
About Janet

Janet Forbes (she/her) is not just a multi-lingual, multi-cultural mongrel, but a published fantasy author, professional worldbuilding consultant, and game developer. In 2017 she co-founded World Anvil (https://www.worldanvil.com), the award-winning worldbuilding, writing and tabletop RPG platform which boasts a community of over 3 million users.
Top image created by Janet Forbes in Canva.









