Nahel bond

The Nahel bond is a bond between a spren and a being from the Physical Realm. It's a symbiotic relationship, granting the spren the ability to manifest into the Physical Realm without losing their mind. In the case of a sapient individual in the Physical Realm, it grants the person the power of Surgebinding as well. It's also a bond formed by, for example, greatshells and Ryshadium.
Originally, the Nahel bond granted power to individuals with no affiliation with one another. Eventually, the Knights Radiant were formed and the Surgebinders were gathered into ten different Orders of Knights, each Order's members bonded to the same type of spren.
== Mechanics of the Surgebinding Bond ==
=== Formation ===
Spren seem to bond with people who share their perspective or personality; however, they also seem to seek partners that would complement them. The bonded spren is more likely to be of the opposite gender to their bond-mate, but this is by no means a hard rule, and there are numerous Surgebinders with same-gender spren, such as Malata with Spark, or Renarin with Glys. Surgebinders are able to instinctively tell their spren apart from others.
A person is able to bond with two different spren, though most spren aren't going to like it. A person can also bond with two spren of the same order, though this will not increase their powers or strength. The Herald Kalak describes such a double bond as being imbricated. He also says that an imbricated Nahel bond can cause strange effects and that he believes there were rules against it prior to the True Desolation. Spren can theoretically bond with another spren, or with two different people at the same time.
How exactly the bond is decided on varies, though it requires volition. Some spren are highly discerning, while others do not pay much attention to the morality of their prospective partner. Some spren choose the people they bond with individually, while others are more organized and make the decision by committee, then send one of their number to bond.
Forming a bond utilizes the cosmere-wide properties of Connection and Identity in some manner; lessening those attributes, such as by storing them in a metalmind, would affect the bond. It is also harder to form a bond with a heavily Invested being, such as a Returned, due to Investiture resisting Investiture. Spren are also less likely to bond with a person using a Hemalurgic spike. This can be contrasted with the Luhel Bond, which primarily utilizes physical matter.
=== Progression ===
The Nahel bond is forged and progressed by the partner stating Immortal Words, also known as Oaths or Ideals, which align with their Order's general outlook and attitude. The first Ideal is identical for all Orders; the latter ones are Order-specific, with Lightweavers in particular stating deep, intimate Truths about themselves rather than Ideals.
As the Radiant states further Oaths, they are brought closer to the spren they're bonded to. The spren's mental capacity in the Physical Realm increases, while the bondholder gains the ability to use Surgebinding more effectively. At some point, the bond also grants the use of Shardblade and Shardplate. However, saying the words - at the very least, in one's mind, though out loud is preferred - is necessary to progress it.
=== Breaking ===
There are some ways to break a Nahel bond. The best-known is when the Surgebinder acts in a manner contrary to the Oaths that they have sworn. This initially manifests by limiting the spren's intelligence and the Surgebinder's capacity to draw in Stormlight. Eventually, it can kill the spren, sending it back to the Cognitive Realm. Revival is possible, albeit difficult, and typically requires the Surgebinder who broke the Oaths to re-swear them, possibly along with progressing to a new Ideal of the Oaths. If a spren is permanently killed by the use of a raysium dagger embedded with a gem of anti-Stormlight, the bond will break, leaving the Radiant traumatized.
Another way to break the Nahel bond is to deliberately forswear the First Ideal; this, too, will kill the spren. If the spren is at a point where it can become a Shardblade, breaking the bond will turn it into a deadeye.
There are some ways to break the bond without killing the spren. Dying while upholding the Oaths -- for example, of old age, or in battle -- will send the spren back to Shadesmar, and severely traumatize it, but the spren will survive and can bond again. A Radiant revived as a Returned would not have their Nahel Bond. Spren are able to retain their sapience in the Physical Realm for a time after the death of their Radiant, but will need to bond again in order to keep it. The spren can also safely break the bond on their own, though this requires a great deal of caution. This will cause the Radiant pain, but will not be destructive to them like it would be a spren.
A Nahel bond can also be passed from one person to another, similar to a seon bond. This has happened a few times in the past, though the mechanics behind it are unknown.
=== Interactions with Dawnshards ===
Individuals who have already formed a Nahel bond are also able to become a Dawnshard, however, this does pose risks for the Surgebinder's spren, as the Dawnshard can use the spren's substance to fuel the Radiant's abilities. This can cause the spren to lose their body in the Cognitive Realm, leaving them as a fragment of themselves. After this, they mainly exist in their Surgebinder's mind and must use the Radiant's body to sense the world around them. They are also stripped of most vocal expression, giving them a monotoned voice.
The pair also loses many of their abilities, including Surgebinding and the Radiant being able to communicate with their mind. They are still able to send feelings and emotions to their spren. Even after the Radiant has given up the Dawnshard, they can still further burn away the mind and personality of their spren for a short burst of Surgebinding.
If the Nahel bond has progressed to the point of being able to summon Shardplate and Shardblade, the Shardblade and Shardplate remain unaffected, even if the spren is completely consumed.
== Powers Granted by the Surgebinding Bond ==
=== Surgebinding ===
The Nahel bond makes a person a Surgebinder. This allows them to breathe in Stormlight, which grants numerous benefits, such as increased reflexes and agility, as well as incredible healing abilities. Moreover, Surgebinders can use Stormlight to fuel their usage of Surges. Each type of Radiant spren grants its Surgebinder two different Surges, with each Surge shared between two Orders of Surgebinders.
=== Resonances ===
Some Orders have additional, unique abilities known as resonances that occur due to the combination of their Surges. Examples of such resonances are the Windrunners' increased number of squires, and the Lightweavers' mnemonic abilities. Rather than being directly caused by the Nahel bond, this is a result of the two Surges interacting to produce an effect together. While some Heralds benefit from the same resonances, others do not - for example, Jezrien will not have a large number of squires, because Heralds do not get squires. 
It's possible that the bond also perfects innate skills of the user, without granting additional skills; for example, an expert spearman would become a spearman without equal, but wouldn't become a master swordsman. While this effect has been observed with Kaladin, it's uncertain whether it holds true for other Surgebinders or orders.
=== Shardblade ===
When the Nahel bond is at a sufficient strength, the bonded spren can instantly manifest itself as a Shardblade, which, unlike dead Blades, is capable of shapeshifting. Known forms range from strictly militant, such as a shield or a spear, to utilitarian, like forks, or plain rods. Moreover, while a human using a dead Shardblade must wait ten heartbeats before the summoning occurs, a living Blade will manifest instantenously.
While in Shardblade form, a spren can communicate with its partner telepathically. The exception to that is the Stormfather, who, while refusing to become a Blade, can communicate with his Surgebinder regardless of the physical distance, directly in their mind.
=== Benefits for the spren ===
While a spren can cross over into the Physical Realm without forming a Nahel bond, the transition leaves them only semi-sapient, with loss of self-awareness, memory and intelligence. There are precautions spren can take to try and minimize the loss of self, but they are not very effective. By forming a Nahel bond, spren are capable of regaining all those things, growing more like themselves the stronger the bond is. However, with a few exceptions (such as the Stormfather), the spren must remain in close physical proximity to their partner to retain their mind. The distance can vary, but some can go upwards of a few miles. If a spren is somehow pushed back into the Cognitive Realm, their Radiant may be able to pull them back into the Physical Realm.
Spren can also anchor themselves to a Radiant while looking for a squire to bond, granting them some level of stability in the Physical Realm. Therefore, unlike the Luhel bond which trades in physical matter, the Nahel bond trades in consciousness and anchoring to the Physical Realm.
== Notable Surgebinders and Spren ==
Surgebinder	Order 	Spren type 	Spren
Kaladin 	Windrunner 	Honorspren 	Syl
Shallan 	Lightweaver 	Cryptic 	Pattern
Jasnah 	Elsecaller 	Inkspren 	Ivory
Renarin 	Truthwatcher	Mistspren 	Glys
Dalinar 	Bondsmith 	unique 	Stormfather
Lift 	Edgedancer 	Cultivationspren	Wyndle
Lopen 	Windrunner 	Honorspren 	Rua
Teft 	Windrunner 	Honorspren 	Phendorana
Szeth 	Skybreaker 	Highspren 	12124
Hoid 	Lightweaver 	Cryptic 	Design
Venli 	Willshaper 	Reacher 	Timbre
Rlain 	Truthwatcher	Mistspren 	Tumi
Navani 	Bondsmith 	unique 	The Sibling
== Trivia ==
* The word "Nahel" is a Rosharan word that means "the bond to divinity", while the word "bond" was added to the term to avoid confusing readers. Assuming the Luhel bond comes from the same root, it can be assumed that the root -hel indicates a bond to something, and na- relates to divinity.
== Notes ==
es:Vínculo Nahel