Everything We Know About Fabrials

Greetings, oh my people, fellow fans of the Cosmere! Welcome back to the next installment of Stormlight Archive review! This week, we’ll take a good hard look at what we know about fabrials, those wonders of modern technology that attempt to make life easier for the… well, probably not the average Rosharan, just yet, but not for Navani’s lack of trying. We’ll look at what they can do, and then what little we know of how they’re made.

Warning: This series will contain spoilers for all of The Stormlight Archive published so far, and will occasionally draw on Words of Brandon for supporting information. I’ll do my best to avoid spoilers for other series, or to mark them if they really need to be included. I make no promises about the comment section; however, I’d request that if you want to include spoilers in a comment, please try to white-text them or at least tag them as spoilers so people can skip your comment.

With that said, let’s get going. What do we know about fabrials, anyway?

A solid basis for the mechanics comes from Khriss’s Ars Arcanum, where she explains five groups of fabrials. I’ll use that as a starting point, but there’s much, much more to dig out, especially since there are some fabrials that appear to be outside the list she addresses. So we’ll start off with what we know of the mechanics of fabrial science as it currently exists on Roshar, look at the ones that don’t fit these categories, and then move into how fabrials are created.


The Mechanical Function of Fabrials

Khriss names three larger groupings of Fabrials, explaining how they work in general, so we’ll start with those.

Altering Fabrials

These are the fabrials that either enhance or diminish some particular effect, be it physical, emotional, or sensational.

Navani’s “pain knife” would be an example of what Khriss refers to as Augmenters. The blades of the knife itself would presumably cause injury, which (I assume) would be augmented by the fabrial to produce crippling pain. Her notes imply that it could be used to cause pain without piercing the skin, though, so… maybe just creating pain? Khriss uses the Vedan “half-shard” shields as another example, in which the durability of the metal is enhanced by the fabrial. The grandbows, or “Shardbows,” which require the enhanced strength of Shardplate to draw, are probably the same; the fabrial strengthens the structure so that the metal doesn’t warp under the strain. I assume that the heater, cooler, and hotplate fabrials, fairly common by the time we reach Oathbringer, are also a form of augmenters… but they make me wonder if “augmenter” is a misnomer, since they seem to generate rather than merely augment the heat or the cold. Maybe we’ll learn more about this later.

The painrial Navani demonstrates on Adolin (The Way of Kings, chapter 60) would be an example of the Diminisher version of altering fabrials; in this case, it diminishes the pain of a pulled muscle without numbing his hand at all. At that time, she mentions hoping to make it useful on the battlefield, as well as in surgeries, and there are later indications that she succeeded.

As we see in Oathbringer, she also made the kind of improvements on it that allow her to include a very small painrial with her wrist-clock bracers. One fascinating note, though: Navani seems to have figured out how to make one fabrial perform both functions: it’s supposed to be a painrial to diminish pain, but she also designed it to generate pain, as she so elegantly demonstrates when captured by Sadeas soldiers in Thaylen City. (And we know she designed it that way, because she mentions testing it on herself.) So… does the mechanism involve two different gemstones in one device, or does she “reverse the polarity” and make the same gemstone have two opposite effects?

Pairing Fabrials

The next type of fabrials also have two aspects. These are fabrials created by splitting a single gemstone and using one half to affect the other. Everything we’ve seen so far involves physical movement of the gemstones, and there seems to be a distance effect—the greater the distance, the less reliable the connection under strain.

The spanreeds we see throughout the series are a good example of the Conjoiner type: when you move one half, the other half moves in exactly the same direction. In spanreeds, when you write with one of a pair, the other one reproduces your exact motions and writes the same thing, wherever it is. Since these are small and light, the distance effect seems to be minimal, and more a matter of delay than strain.

The opposite type is called a Reverser and, as you might guess, mimics the action in reverse. We first observe this in Words of Radiance chapter 35, where Navani is testing her archery tower design. The split gemstones are placed in two different platforms—one mounted up on a parapet, the other on the ground. When the fabrial is activated, pulling the upper platform down causes the lower one to rise. Navani seems to have great plans for this idea, but we only see it in the testing stages here. She does note that distance and strain are significant issues for something this large, but she hopes that they can be used reliably on the Shattered Plains, with the relatively near proximity of warcamp to battle. As far as I can recall, we never got to see them used. There is some indication that the lifts in Urithiru may use something of the same technology, with counterweights connected to the ifts by fabrials rather than physical means.

Warning Fabrials

The only one I know for sure fits in this category is the one we saw in The Way of Kings, Interlude 4, which Rysn set up for her babsk, Vstim; she was able to filter out the people in their camp, and then set it to give warning if anyone else approached. Help me out, here: have we seen this effect anywhere else? I couldn’t find anything.

Attractor Fabrials

This is a new style that first appears in Words of Radiance, and (as you might guess from the name) are fabrials that attract a specific substance. (For reasons unknown, Khriss doesn’t seem aware of these. However, WoB says that our favorite author just forgot to update the Ars Arcanum to include them. If you want to go breaking the fourth wall and stuff.) We see one in action, when Shallan first visits the Ghostbloods warcamp lair in Chapter 43; she sees a fabrial that collects the smoke from the hearth. Later (Chapter 67) Navani mentions the idea of using that same type of fabrial, except with water instead of smoke, to build a pump mechanism. Much later, then, we see that if she hasn’t got a pump going yet, she has built a highly effective dehumidifier—so effective that it draws the humidity of the Weeping from the air in a partially enclosed pavilion, allowing Dalinar’s archers to use bows during the Battle of Narak.

Implicit in the concept of Attractors is the existence of Repellor fabrials. While we haven’t seen any of these (that I can think of, anyway), another WoB confirms their existence.

Other Modern Fabrials

There are a small handful of other fabrials that I’m not sure where to place. Clocks, ceiling fans, floodlights, and stabilizers are all mentioned, and I’m not sure what makes them… tick, as it were. At the time of Kaladin’s childhood, clocks are known but not terribly common; his father has the only one in Hearthstone, and no one but Lirin cares about timing that accurate anyway. The rarity is probably a combination of wealth and the availability of fabrial technology; while it’s clear that great strides are being made in fabrial technology, it’s probably only readily available to those with the money (mostly up dahn and upper nahn) and the access (cities more than rural areas). In any case, we see a lot more clocks around when we get to the later books. But I have no idea how they work, or how they could fit into any of the above categories. Likewise, what drives a ceiling fan? How does a floodlight work that’s different from a mere lantern? And what kind of fabrial behavior allows you to stabilize an ocean-going ship‽

There’s also a fabrial specifically for draining part of the Stormlight from a gem—apparently used by Hatham to make sure his jewelry has just the right subdued glow. Oh, and let’s not forget Navani’s emotion-reading bracelet design in The Way of Kings—maybe that’s a sort of Warning Fabrial, since it reads the emotions of people nearby? Or maybe it’s a modified Attractor, lighting up when a specific emotion triggers it? I don’t know.

Ancient Fabrials

Then there are the magnificent fabrials of the ancients, handed down for generations upon generations, and only barely understood. These are the things that, at best, modern Rosharans are able to use; they have no idea how to recreate them nor adapt their technology. Soulcasters are the obvious and familiar one, of course; while the artifabrians are sometimes able to repair a broken one, they have no idea how they are made. The Regrowth fabrial appears in several of Dalinar’s visions, and Nale apparently has a working one in his possession, which he uses on Szeth. Finally, there are the Oathgates, which are apparently controlled by some kind of intelligent (and huge) spren, and… Urithiru. We don’t really know this last, I guess, but when Renarin theorizes that the whole tower, with its crystal veins and multi-gemstone-pillar heart, is a whole collection of fabrials that make one great City fabrial, I believe he’s right. It just makes so much sense to me.

And that’s the best I can do at categorizing all the fabrials identified in the books so far. Did I miss any?


The Art of the Artifabrian

It’s all well and good to know what fabrials do, but how are they made? We’ve been learning in bits and pieces as we go along, so lets just summarize it here, shall we? One quick note: In the engineering terminology, the gemstone itself is actually the fabrial, and the rest of the apparatus it powers is the machine, but common usage dubs the whole thing “fabrial.” I’m using the latter sense, and specifying the gemstone when the it needs to be distinguished from the mechanism.


According to modern Rosharan technology, in order to create a fabrial, the first thing you have to do is trap a spren. ::gulp:: So far as we know, all of the modern fabrials make use of the plentiful types of non-sapient spren. These are the spren of physical phenomena (heatspren, coldspren, gravityspren, etc.) and of emotions or sensations (painspren, angerspren, joyspren, anticipationspren, etc.)

Trapping spren seems to involve two primary requirements. One, you need a gemstone with the color and cut most appealing to the particular kind of spren you want to attract.. For example, the heatspren used in the heater fabrials apparently prefer rubies, and they probably all use a specific cut. Two, you also need something the spren loves—basically, you need the thing that draws it to the Physical Realm in the first place. Using the same example, one would assume you provide a source of heat near or around the gemstone, I guess? When you combine these two things, along with patience and perseverance, you trap a spren in a gemstone.

Once you have the trapped spren, the mechanism uses metal—much like electricity—to transmit the desired effects. Many of the fabrials are described with “wire cages” for the gemstones, for example, and most of Navani’s creations seem to be metal, sometimes set in leather like the clock/painrial bracers she and Dalinar wear.

As with all cool things on Roshar, they’re powered by Stormlight. One of Navani’s designs specifically shows a cover which can be removed in order to recharge the gemstone, but most don’t say anything. It makes me wonder: do people have to take their fabrials out in highstorms to recharge them? Do they remove the gemstones from the mechanisms and take those out in the highstorm? Do they have some way to use a gemstone without a trapped spren to infuse a gemstone with a spren, sort of a battery effect? Maybe that thing of Hatham’s can be used more generically to transfer Stormlight from one gemstone to another? As an engineer myself, these are practical questions I have, and as near as I can tell, they haven’t yet been answered. (Correct me if I missed it!)

Moral Questions

This whole process raises a number of thorny moral questions for the reader. Is it okay to trap spren? Are they slaves once they’re harnessed in a fabrial? Are these kinds of non-sapient spren, the ones that merely follow the emotion, sensation, or physical object which attracts them—are they really any different than, say, the fish trapped in your fishtank? Is some level of intelligence required in order for “slave” to have any meaning? I have, tentatively, come down on the side that says this is morally not much different than using a wind turbine or solar panel to generate electricity. At worst, it might compare with using horses or oxen to pull a wagon or a plow (okay, a century ago, but whatever). That is, of course, based on the assumption that these truly are non-sapient spren, aware only of the thing that attracts them, and that this is the only kind of spren the artifabrians can capture.

What About the Ancient Fabrials?

That seems to be a generally valid assumption for modern technology, so I’m okay with it until I learn differently. It does, however, raise other questions. These modern fabrials mostly mimic things that could, albeit with more difficulty, be done by strictly mechanical means. What about the ancient fabrials? What kind of spren did they trap to make a Soulcaster, or a Regrowth fabrial? Or an Oathgate? Or a city-tower? Or are those on a different level completely?

Some few answers seem logical. Dalinar saw Regrowth fabrials used in some of his visions during Desolations. Given that they were mostly being used by Knights Radiant, I cannot believe that they deceptively trapped the same kinds of sapient spren who could bond to form new Radiants, but… then what? Word of Brandon says that, like Soulcasters, fabrials could be made to replicate all of the Surges used by the Heralds and the Radiants. What spren powered those?

Or is there something different going on with them? We saw Dalinar use this knowledge of fabrial construction to pull in Nergaoul and imprison him in the perfect ruby called the King’s Drop, so … there’s that: Spren, even great spren, can be sucked into a gemstone. On the other hand, we know that they habitually replace the gemstones in the Soulcaster fabrials if they crack, as well as actually repairing the devices when they’re damaged. (Navani explains in a message to Jasnah that Soulcasters need to have their gem housings realigned “more often than you’d think.”) No big deal… until you realize that, if they can replace the gemstones with impunity, there are clearly no spren trapped in the gemstones. And if they can repair the metal parts as well… well, where would the spren be?

If the ancient fabrials don’t use trapped spren, what are they and how do they work? This seems to be a highly significant difference between the ancient fabrials and the modern ones, and it sure would be nice to know what it means. As usual, there is still a lot we don’t know about the subject of this week’s study. It seems to be the story of my life.


Well, that one was a little shorter and more manageable. I hope you enjoyed it as much as I enjoyed the research! Next week at this time, we’ll take a little different tack: Drew McCaffrey will bring you up to date on The State of the Cosmere. Sort of a … Cosmere 201 seminar, which we can all use, from one of the masters of Cosmerology. The following week, I’ll be back along with Megan Kanne to take a good hard look at the secret societies functioning on Roshar. In the meantime, Comments Ahoy!

Alice is a Sanderson Beta-Reader, mega-fan, and occasional theory-crafter. She takes great pride in the moment at Emerald City Comic Con 2018 when, in conversation about some disputed fan interpretation of a scene, Sanderson said, “You’re right. Just tell them I said, ‘Alice is always right.’” She is also an administrator of two Facebook fan groups: The Stormlight Archive (spoilers allowed for Stormlight books only; everything else has to be spoiler-tagged) and the Storm Cellar (Sanderson fans loosely centered around the Tor rereads, spoilers for all Sanderson books allowed).


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