(This post has been adapted into a video essay.)
A few years back, fantasy author Brandon Sanderson (Mistborn, Wheel of Time, Stormlight Archive) wrote a series of essays describing laws of magic systems. In the second of these essays, Sanderson posits that limitations are of greater importance than powers when it comes to effective magic systems.
Limitations are more important than powers
This notion is in agreement with a basic storytelling principle that I think many of us (readers and writers alike) instinctively understand about storytelling: what a character can’t do is often more interesting than what they can do. Limitations and weaknesses are what drive struggle, vulnerability, conflict, and tension, many of the wonderful elements we love to see present in a story.
As a bit of an aside, I believe that this is why there is some disdain for for “wish fulfillment” and “Mary Sue” type characters, as these are narratives that are often inspired (and defined) by what the characters can do, often to the complete exclusion of any limitation or weakness.
It’s common to define and recognize magic systems based on powers. A prominent example of this can be seen in the anime/manga series Death Note (spoilers follow). The main magic present in Death Note is a notebook that has the ability to kill people, and protagonist Light also has the ability to specify the victims’ time and cause of death. These are interesting story hooks. But I would contend that Death Note is not a story about the powers of the Death Note as much as it is a story about the Death Note’s limitations.
What are the limitations of the Death Note? For one thing, Light needs to physically write the name of his victim in the book in order to cause death. He can’t just will people to die, or cause people to die by performing some trivial action like snapping his fingers. The Death Note, by its nature, leaves behind a paper trail, and thus represents a liability for anyone under scrutiny of investigation. Thus, when his home comes under surveillance, Light is forced to come up with creative ways to continue to write names in the Death Note while avoiding detection. In a sense, Light’s continued use of the Death Note is requisite, in the sense that if people stop dying when he is under scrutiny, then it becomes apparent to the investigation team that Light is somehow linked to the murders. This limitation of the Death Note represents a manner in which Light may be caught. It’s a source of tension.
The other major limitation of the Death Note is that Light needs a name and face in order to kill. This is ultimately what drives the conflict between protagonist Light and antagonist L, as Light cannot use the Death Note to eliminate L without knowing his name. This limitation of the Death Note also forces Light to creatively to circumvent this limitation, as becomes the case with the Raye Penber arc.
Death Note also provides a good example of a magic that is tied to a powerful cost. Light has access to another magic power apart from the Death Note itself: the “shinigami eyes,” which allow the user to see someone’s name by looking at them. However, this power comes at the cost of half of his own remaining lifespan. Light decides not to trade half his remaining lifespan for the shinigami eyes, which reinforces what we are taught about Light during the series: first, by declining the offer, he is demonstrating a certain level of pride, or confidence in his own ability. The ability to see someone’s name simply by looking at them is a potent power that would greatly advance Light in the pursuit of his immediate goals, but he’s confident that he is skilled enough to defeat his foes without resorting to this costly power.
Second, Light’s decision to decline the shinigami eyes reinforces the idea that Light’s mission to eliminate criminals isn’t ultimately driven by altruism, but by megalomania. Light doesn’t consider it enough to simply create a “better” world that is free of criminals; he also wishes to preside over this new world as emperor. Making the trade for the shinigami eyes would allow Light to more quickly overcome the immediate obstacles in his path, so Light is forced to make a decision: does he take the eyes and achieve his vision of a “perfect world” that much sooner? Or does he decline the eyes and give himself more time to sit on the proverbial throne? He opts for the latter, and that is a powerful statement about his character and true motivations.
Later in the story, we see other characters who also receive the offer to trade half their remaining lifespan for the shinigami eyes. And each of those characters, in turn, reveals an element of their character and motivations based on the decision that they make.
The conflict between Light and L is one of the most interesting parts of Death Note, and if Light had the ability to see others’ names, that conflict would end quite swiftly. However, because the power is tied to a significant cost, it can be included in the story without undermining that central conflict.
Limitations are what drive the conflict of Death Note: Light must continue to write names in the Death Note without alerting the investigation team that is monitoring him, and Light must also ascertain L’s true name. Without these two limitations in Light’s magic power, we don’t have much of a story. With them, we have a manga that has become one of the most successful manga of all time, running for 108 serialized chapters, selling over 26.5 million copies, and receiving numerous accolades.
A story with fantasy elements doesn’t necessarily require detailed rules defining the limitations of the powers that exist within its universe. But if you want to tell a story that is about conflicts based around magic powers, a good first step would be to consider what the limitations of those magic powers are.