Suppression fabrial

A suppression fabrial is a specialized device on Roshar that can suppress Surgebinding.
== The Sibling's Fabrial ==
===Design and Effects===
The most notable example of a suppression fabrial is a powerful device that is part of the Sibling and is used to protect Urithiru. The physical form of the fabrial is a distinctive construction of garnets set into the crystal pillar at the heart of Urithiru, a place formerly called Ur. It is placed prominently on the pillar, near eye level. Destroying the gems removes the fabrial's effects. Unlike fabrials created by humans, the gems do not contain trapped spren.
When the fabrial is active, rhythms and the use of Voidlight are disrupted by a suppression field. This typically incapacitates Fused, Regals, and Unmade that are inside its range. The suppression field has a finite area of effect originating at the fabrial, with an abrupt "invisible wall" at its limit. The exact mechanism that the Sibling uses to fuel their core systems (including the fabrial) is unclear, but it involves Towerlight. Based on its effects, the fabrial would presumably fall into the category of a diminisher fabrial. The fabrial seems to have a variable power level; with sufficient power the field can encompass the entirety of the massive tower plus an area extending outwards at least hundreds of yards. Surgebinders that do not use Voidlight are not known to be affected.
The fabrial is not completely foolproof. Some of the Unmade are able to resist the effects, as can other highly Invested individuals. Additionally, the suppression field created by the fabrial affects all Surges, but it does not do so equally. For example, when the Sibling was weakened during the True Desolation, the mavset-im that use Illumination had their illusions disrupted near the tower, while the makay-im that use Cohesion were still able to use their powers effectively. This is likely related to the relationship of each Surge to Honor and Cultivation.
===Inversion===
It is possible to corrupt the Sibling and invert the fabrial, causing it to incapacitate users of Stormlight rather than Voidlight, including Knights Radiant. This is accomplished by pushing Voidlight into the Sibling's system, shifting parts of it to the tone of Odium. This was once impossible, but the Sibling lost their ability to create Towerlight during the False Desolation, weakening them, and Raboniel realized that she could overtake their system. The effects of the fabrial feel like an oppressive pressure of darkness on both spren and Surgebinders. Radiants inside of the suppression field are unable to Surgebind or summon a Shardweapon, and are usually knocked unconscious. 
The inversion of the fabrial reveals a few additional properties of its effects. Other fabrials, which are typically fueled with Stormlight, stop working within the suppression field. Fabrials made from Enlightened spren can still be used, but only if they are fueled with Voidlight. People who have bonded a dead Shardblade are unable to summon it, though an unbonded one will remain unaffected. The Oathgates are not disabled by the fabrial, and they can be operated with an Honorblade.
Affected Radiants that remain conscious are able to breathe in Stormlight and hold it in their bodies. It will continue to heal them, although the internal healing effects diminish if the Sibling's corruption increases. Spren that have a Nahel bond with a Radiant are pushed into the Cognitive Realm and enter a deep sleep-like state. Radiants that are far enough in their oaths are able to resist the effects, and their spren may be able to remain in the Physical Realm with some effort. 
If a singer is both a Radiant and a Regal, they feel a "wall" that prevents the use of Stormlight, but they are otherwise unaffected by the suppressor, even at the First Ideal. Those using an Honorblade will still be able to Surgebind and summon their blade. Lift, a unique Surgebinder who uses Lifelight instead of Stormlight, is unable to use Abrasion and can only use Progression with great difficulty. The reason that the fabrial seems to affect Lift when it is attuned to Stormlight is unclear.
== Fused Replicas ==
Raboniel discovered suppression technology thousands of years before the True Desolation by studying the defenses of Urithiru. Although Raboniel was put to "sleep" before perfecting a replica fabrial (because she was thought to have gone mad), other Fused were able to use her research to create an unknown number of small-scale prototypes.
=== Design ===
The suppression fabrials used by the Fused are portable and relatively delicate. They include four cut garnets arranged in a layout similar to that of the Sibling's fabrial. The garnets are set into a cylindrical shaft; two angular pieces extend from the top of the shaft, making the entire device superficially resemble a tuning fork. The fabrial is activated by twisting a gem at its base and glows violet-black with Voidlight when in use. The devices are made of an unknown metal or alloy; if they are assumed to be diminisher fabrials, they likely include tin. They can be given tripod legs. The Fused use Enlightened spren to power the devices.
=== Effects ===
Like the inverted Urithiru fabrial, the replicas affect Radiants who Surgebind with Stormlight. They also affect Lift. Presumably, they could be repurposed to stop Fused from Surgebinding.
The replicated effects are generally similar to those of the Sibling's fabrial. Radiants feel a smothering sensation and abruptly lose the ability to Surgebind. Their bonded spren lose their sapience and cannot be summoned as a Shardblade. Radiants and spren that are farther along in their Oaths have some resistance to these effects. Stormlight inside of a Radiant's body remains there, and can still provide a few benefits such as substituting for oxygen. The primary limitation of the replicas is that their range is much smaller than the Sibling's original design, roughly the size of a room. Some of the effects may be less pronounced than those of the Sibling's fabrial; Kaladin and Syl seem to have more difficulty resisting the effects of the original fabrial as compared to one of the replicas.
==History==
=== Early History ===
The Sibling's original fabrial was considered part of their being. It was one of a number of fabrials that were integral to the defenses of Urithiru, and took many years to perfect. It was created to prevent Fused and potentially the Unmade from entering the tower. The fabrial seems to have functioned well throughout the Desolations, as the Fused were well aware of its effects. During the False Desolation, the imprisonment of Ba-Ado-Mishram ripped out both Connection and Identity from the singers; this had unintended consequences, including injuring the Sibling such that they could no longer create the Towerlight that fueled Urithiru's systems, including the fabrial.
At some point (presumably during the Heraldic Epochs), the Fused scholar Raboniel was able to somehow study the Sibling's defenses, and she discovered the underlying technology of the suppression fabrial. The Sibling was aware of Raboniel's level of knowledge, and was afraid of her. Around the time of the Last Desolation, Raboniel was thought to have gone mad, and was compelled to stay asleep indefinitely. However, after the other Fused returned to Roshar during the True Desolation, they were able to build an unknown number of prototype suppression fabrials based on her research, and nearly perfected them.
=== True Desolation ===
After the coalition of monarchs moved into Urithiru, they were able to identify the garnet structure in the crystal pillar as a distinct fabrial. Navani deduced that it was related to defense from the Fused, but she did not know exactly what it did or how to activate it.
In , one of the prototype fabrials was tested in Hearthstone during an attempted ambush of Kaladin by Lezian and other singers. The fabrial worked as intended, but Kaladin was still able to defeat Lezian without his powers. Coincidentally, the only Radiants present at the time were Godeke (who was unconscious) and Lift; this likely obscured the full effects of the replica, as Kaladin and Lift were the only Radiants who were later able to resist the Sibling's corrupted fabrial. Kaladin's team was able to deactivate the fabrial and deliver it to Navani for study. The Nine were unhappy that the device had been lost, especially since Leshwi pointed out that it could lead the humans to new discoveries. Lezian, in an attempt to save face, incorrectly claimed that the device had not worked.
Despite Navani's knowledge of fabrials, the design of the Fused fabrial baffled her at first, although she noted its similarities to the garnets in the Sibling's crystal pillar. She had Rushu and other top scholars study the fabrial; they were able to identify the Enlightened spren in the fabrial, although it refused to interact with them. By this time, Navani assumed that the fabrial in the pillar was also a suppression device, but she could still not figure out how to activate it.
Around the same time, Raboniel unexpectedly reappeared and immediately proposed a plan to the Nine to invert the Sibling's fabrial and invade Urithiru. Although the council was somewhat skeptical at first, they allowed Raboniel to proceed. After testing the edges of the tower's defenses, Raboniel and her strike team were able to infiltrate the tower and reach the crystal pillar room. The Sibling was aware of the incursion, but could not strengthen the fabrial enough to keep the Fused out. With a great deal of effort, Raboniel was able to break through the Sibling's resistance and infuse the pillar with Voidlight, targeting the suppression fabrial first. Her inversion of the fabrial suppressed the use of Stormlight, leaving the tower's Radiants unconscious. Navani suggested a last-ditch effort to recapture the pillar room and fix the fabrial, but the plan failed despite a noble effort by Teofil and his squad. Dalinar and other Radiants who were away from the tower could not approach it without losing their powers.
Navani was captured, but she was able to speak to the Sibling, who explained what Raboniel had done. After working with Raboniel to make several research breakthroughs regarding the nature of Lights, Navani was able to convince the Sibling to form a Nahel bond with her, making Navani a Bondsmith and restoring the pair's ability to create Towerlight. She was able to force the Voidlight out of the Sibling's system using the tone of Anti-Voidlight, and her practical knowledge of fabrials allowed her to immediately return the suppression fabrial to its original purpose, surprising the Fused and restoring control of the tower to the coalition.
== Notes ==