Nen

Nen (念 Mind Force) is one of the defining features of the manga Hunter × Hunter by Yoshihiro Togashi. The term refer to both: (1) the ability of using and manipulating the life energy (known as Aura) present in the body of the user. (2) the Aura itself under this ability.

Creation
In the world of Hunter × Hunter, Aura is the life energy produced by all living bodies, it is considered a vital energy that results from simply being alive. If one were to lose all their aura, it would be equivalent to using up all the energy that is keeping them alive, which would be fatal. Aura from all parts of the body has a tendency to flow together, producing one mass of energy. This happens without the individual's awareness, and will simply leak out of their body slowly. The pores or points on the body from which aura flows out from are called aura nodes (Shouko). Controling those nodes is the first step to be a user of Nen.

Learning, controlling, and seeing
A Nen student trains to manually open and close their aura nodes so that they can control the flow of their aura.There is two methods to do so. One normally learns this process gradually, learning to control the nodes through meditation (Zushi was doing this method). The second method is by having one receiving an influx of aura from an experienced user that forces these nodes to open; despite how quickly it works, the method is typically frowned upon due to its danger to the student (Wing done this to Gon and Killua). Gently jolting open one's aura nodes forces the new user to learn to control their aura flow, else risk suffering severe exhaustion or death. Once one has opened their aura nodes, they will be able to see their aura as a shroud surrounding the body (this is because the nodes in their eyes are opened).

Some people are able to discover and learn to manipulate their aura on their own, without any teaching or guidance from another Nen user.

Geniuses
Nen is like any other skill, in that there are those who will learn it faster than others. There are also individuals that can use facets of Nen without having any formal training and are typically known as "geniuses," "psychics," or "superhumans." This can be anything from inadvertently being able to use the basic techniques of Nen or unconsciously developing a unique Nen ability that can be used without really understanding how or why one is able to do so. Geniuses within the series include Neon Nostrade and Komugi.

What affects Nen
Although the production of aura is unconscious and constant by all living beings, it is not only life energy. Aura carries with it the desires and emotions of the one who deploys it, which is what allows for Nen to have incredible versatility to those who develop their skill at using it. Nen is also heavily influenced by mental condition and emotional state. A basic application of this phenomenon is that one can channel their aggression or malice into their aura and deploy it towards another person (i.e. bloodlust). The other person will then be able to feel that bloodlust as if it were physically palpable, and if unable to keep it from their own body by deploying their own Nen, may be physically harmed by it.

Conscious strengthening of Nen through Limitations
Nen responds to the goals and strengths of the desire of its user. As a result, a user can make a commitment that results in an increase in their abilities. If a user, for example, modifies their own body in such a way that an individual skill seems more imposing when used, their Nen ability will become correspondingly more powerful (e.g. Franklin cutting off his fingertips to make his emission ability stronger).

It is also possible to increase the overall strength of an individual skill by stating an oath that imposes even more conditions on it. For example, if a user consciously decides something along the lines of "I will only use this skill on Thursdays," or "I will only use this skill against short people," and manage to abide by the rule, that particular skill will become stronger. These conditions are called "Contracts", which can increase the raw power of an ability. Theoretically, the more restrictive the contract, the greater the enhancement in power. It is also implied that limitations that carry great meaning or are tied to emotional states also bring about a greater benefit. Furthermore, contracts which contain some sort of 'punishment' (i.e. "I will die if I break this rule") will strengthen the ability more.

An example of this is the character Kurapika, who swore by 'death' not to use one ability of his, 'Chain Jail', on anyone but the Spiders. It should be added that even though a Contract adds further limitations to using one's Nen ability, the oath/s are not the primary conditions for the ability to be activated and acts only to enhance the power of the ability.

The Unknown
Though Nen is influenced by one's mental condition and emotional state, it is difficult to judge exactly how these factors effect Nen. In certain instances, these factors may even lead to one exceeding the 100% limit cap. However, one using his powers beyond their capacity will ultimately cause strain. Potentially, this could become either a weakness or fatal to the user.

Nen also doesn't necessarily disappear following death. In fact, sometimes death can reinforce an ability's strength. If someone dies holding a deep grudge, his Nen will remain and seek out the object of his hatred.

Basic Techniques
There are four fundamental techniques one must learn to fully grasp Nen. Everything else, including a Nen user's specialized skill, is based on the basic manipulations of one's aura flow. These are the first techniques that are taught to any student of Nen.

These basic techniques, in order of study, are: Ten, Zetsu, Ren, and Hatsu.

Often, for an experienced person able to use Nen, these basic techniques are second-nature. For example, a beginner must learn to use Ten, and concentrate to maintain it; whereas someone with experience will practically always be in a state of Ten, even during sleep.

Ten
Once a person has had their aura nodes opened, they must learn to keep their aura from leaking away from their body. Ten (纏, Envelop) is the process of keeping the nodes open, but also having aura flow through and around the body rather than away from it. Once maintained, it creates a shroud around the user that feels similar to standing in lukewarm, viscous fluid. Having a shroud of aura surround the body is the most basic defense against the physical or emotional attacks from other users of Nen. Ten maintains youthful vigor and reduces one's aging; since the energy powering the body no longer leaks away, one can keep the body from breaking down and deter the aging process. Through frequent meditation, one can improve the quality of their Ten.

Zetsu
While Ten allows a user to keep aura from leaking away from their body, Zetsu (絕, Suppress) stops the flow of aura from their body altogether. By closing all of their aura nodes, the user is able to stop almost all outflow of their aura like water from a valve. Since the user is no longer surrounded by their own aura, they are more sensitive to the aura of others. This can be useful when tracking another person, and it will also prevent other users of Nen from noticing them. Zetsu can also be used to relieving fatigue, since it forces the body's external layer of aura to be fully contained within. However, since Zetsu involves shutting off one's aura, it can be dangerous due to it leaving the body defenseless against any aura attack. Even a weak attack enhanced with Nen could do massive damage.

Ren
Ren (練, Refine) is a direct application of Ten. Since a user is capable of keeping aura from leaking away from the body, it's also possible for them to produce more aura around themselves without having to worry about losing it. Ren focuses on outputting a high amount of aura and keeping it on the body, expanding the size and intensity of it. If Ten is considered to be purely defensive, then Ren typically what is used for offense. This increases the user's physical strength and durability and provides a large pool of aura for any advanced techniques or individual skills they decide to use.

Hatsu
Hatsu (發, Release) is the release or transmission of one's aura so it can be projected to carry out a certain function. In essence, Hatsu is one's personal expression of Nen that creates a special and unique ability (colloquially called a Nen Ability). A good Hatsu should reflect a person's own character; one can never truly master Nen if they only copy other people's abilities. There are six types of aura, and the aura of every individual is aligned with a specific category. Upon learning their affinity, one can set about learning to apply Nen in a unique way that suits their personality, which can develop into a unique skill.

The most popular way (and the only sure-fire way seen in the series) of determining one's aura type is through water divination. The test requires a leaf floating in a glass of water. It consists of a student placing their hands around the glass and performing Ren. The effect of one's Ren on the water or glass determines the student's affinity. If the volume of the water changes, the user is an Enhancer. If the color of the water changes, the user is an Emitter. If the leaf moves on the water's surface, the user is a Manipulator. If impurities appear in the water, the user is a Conjurer. If the taste of the water changes, the user is a Transmuter. If a completely different change appears, the user is a Specialist.

A person's aura only belongs to one of these six categories and thus it is better to base a Nen ability on the category their aura is akin to. Using abilities not of your primary aura type makes you generally less proficient at using them. By creating an ability that one isn't suited for, one risks stagnating their potential through by overloading their capacity for using Nen--something Hisoka calls "Memory Overload."

There are numerical approximations given by the manga to indicate just exactly how efficient one would be at using aura abilities that one is not born into. Starting at one's own aura type, one has the potential to be 100% efficient at using abilities based in that category alone. Then looking at the category chart (see below), one has the potential to be 80% efficient at using aura types adjacent to your primary type, 40% efficient at the opposite or farthest category, and 60% efficient in the two remaining categories. Specialization is typically unusable for non-specialists because it is impossible to partially use; one either can can't use Specialist abilities. However, Conjurers and Manipulators have 1% efficiency potential for Specialization due to being adjacent to it.

Hisoka also claims that he is able to judge a person's Nen type based on their personality (so according to him, all people of one Nen type are generally of the same personality type). However, he states that this method is similar to trying to find someone's star signs or blood type just from personality analysis--it's not always correct. According to his theory, Enhancers are determined and simple, Manipulators are logical people who advance at their own pace, Transmuters are whimsical liars, Emitters are impatient and not detail-oriented, Specialists are independent and charismatic, and Conjurers are high-strung.

Enhancement (強化 Kyōka)
If a student increases the quantity of water in the glass during their water divination, they are an Enhancer. Enhancement is basically the ability to use aura to increase the natural abilities of an object or one's own body. Therefore, Enhancers are able to greatly increase their physical attack and defense, and are best suited for close-melee combat.

Enhancement is the most well-balanced category, allowing users to spread themselves evenly between offense and defense and become very strong using only simple abilities. Examples of more complex Enhancement abilities include enhancing a person's ability to repair themselves.


 * Notable Enhancers include:
 * Gon Freecss
 * Kastro
 * Uvogin
 * Phinks
 * Nobunaga Hazama
 * Palm Siberia

Emission (放出 Hōshutsu)
If a student changes the color of the water in the glass during their water divination, they are an Emitter. An affinity for Emission means that a user is capable of controlling the deployment of their aura while separating it from their body. Aura usually decreases in intensity very quickly when it is separated from the source body, but strong Emitters can separate their aura from their body for long-periods of time and still be able to maintain it.

An application of this is the ability to throw giant balls of aura. Emission abilities are commonly mistaken for Conjuration abilities. The two, however, are fundamentally different. Objects created by Emitters are made of pure aura, believed to be invisible to normal people, and requires Manipulation skills to control.


 * Notable Emitters Include:
 * Leorio
 * Franklin
 * Razor
 * Melody
 * Pokkle
 * Shachmono Tocino

Manipulation (操作 Sōsa)
If a student moves the leaf floating on the water in the glass during their water divination, they're a Manipulator. Manipulation is the ability to control living or non-living material. Abilities belonging to Manipulators allow the user to control living or non-living things in a certain way, the main advantage being able to 'manipulate' enemies. The degree of control is principally determined by a condition that usually puts the manipulator at risk (attaching objects on the enemy, touching the enemy in a certain way) and of course the larger the risk, the better the degree of control. For example Illumi's ability requires him to merely throw needles into his enemy's head which is not as risky as planting a kiss on the enemy, and as a result, Illumi's control is less powerful than Vezze's (Illumi can only implant images into the enemy's brain and change their faces whereas Vezze can make a man obey her every command full-heartedly).


 * Notable Manipulators include:
 * Illumi Zoldyck
 * Shalnark
 * Kalluto Zoldyck
 * Shoot McMahon
 * Zushi
 * Squala
 * Baise

Conjuration (具現化 Gugenka)
If a student creates an object in the water in the glass during the their water divination, they are a Conjurer. Conjuration is the ability to create a physical, independent, material object out of one's aura. Once a person has mastered the conjuration of a certain object, they can conjure it and dispel it in an instant, whenever they want. It is believed that conjuration is the only way in which Nen can create things which ordinary people (unaware of Nen) can see and touch. Furthermore, objects/entities materialized by this technique have a subtle "independence" to them. This means that they can continue existing even if they were at a considerable distance from the Conjurer, or even if the Conjurer themselves are not aware that they have yet to be de-materialized. However the use of In can hide an object materialized from aura from experienced users of Nen.

Conjured objects can have special abilities imbued into them. For example, the Phantom Troupe bandit, Shizuku, is able to conjure a vacuum cleaner that can infinitely suck up objects, but with the condition that it can't suck up living things. Similar to manipulation, conjuration abilities tend to be very specific, complex, and conditional. Conditions can be imbued into conjured objects to make them stronger. Kortopi, for example, is able to materialize a perfect copy of any non-living object that he touches. However, all of his materialized objects will automatically disappear after 24 hours.


 * Notable Conjurers include:
 * Kite
 * Kurapika
 * Netero
 * Knov
 * Shizuku
 * Kortopi

Transmutation (変化 Henka)
If a student changes the taste of the water in the glass during their water divination, they're a Transmuter. An affinity for transmutation means a person can change the properties of their aura to mimic something else. Similar to emission, things created via transmutation are still pure aura. Transmutation is often mistaken with conjuration due to their similarities, a simple way of thinking about it would be that transmutation allows your aura to mimic properties of a substance, whereas conjuration allows you to change your aura into actual substances. Transmuters can copy the properties of real things. For example, Killua Zoldyck uses his aura to copy the properties of electricity. Transmuters can also give their aura properties that don't necessarily mimic real things; Hisoka's "Bungee Gum" copies and combines the properties of rubber and gum. Transmuted substances are invisible to people unaware of the existence of Nen.
 * Notable Transmuters include:
 * Killua Zoldyck
 * Hisoka
 * Zeno Zoldyck
 * Genthru
 * Biscuit Krueger
 * Machi
 * Feitan

Specialization (特質 Tokushitsu)
If a student causes some other effect during their water divination, they're a Specialist. It is possible that the effect that occurs can give some insight into how they should direct their ability. Specialization is anything that doesn't belong into the other five categories. This is the most vague Hatsu category. For example, Kurapika's specialization ability allows him to use all Hatsu types at 100% efficiency. Chrollo Lucilfer specialization ability is to steal any other Nen ability. Neon Nostrade's specialization ability is unique, it has almost no relevance to any of the other five Hatsu types. It is possible to become a Specialist later in life, although it is more likely for Manipulators or Conjurers which is why it is placed at the bottom of the chart.


 * Notable Specialists include:
 * Chrollo Lucilfer
 * Pakunoda
 * Knuckle Bine
 * Neferpitou
 * Kurapika (only in Emperor Time status)
 * Meryem

Hatsu abilities

 * Using more than one Hatsu type

A lot of Nen abilities use more than one Hatsu type. Common combinations include manipulation and emission (allowing the manipulation of objects from far away) and manipulation and conjuration (allowing the manipulation of conjured objects).


 * Within human boundaries

No Nen ability can be "beyond human boundaries." What this means is that you can't have an ability that is limitless. For example, you can't materialize a sword that can cut through anything. However, if you can set very strict conditions on it, then you can materialize a sword that can cut through anything given that the conditions are met. For example, Kurapika was unable to materialize an unbreakable chain. However, he was able to materialize a chain that was unbreakable by any Phantom Troupe member. Shizuku is able to materialize a vacuum cleaner which can suck up any nonliving object not created by Nen.


 * Conjuration/Emission/Transmutation

These three Hatsu types tend to cause a lot of confusion to some people. To put it in short, a conjured thing is solid and material, anyone, whether or not they can use Nen can see it (unless In is used to conceal it); a transmuted thing is pure aura that copies the properties of other things, whilst emission abilities shoot pure aura able to be kept distant from the user's body.


 * Kastro's Doppelganger [Conjuration] - The Doppelganger was solid, ordinary people could see it, and it could be separated from the real Kastro as long as it stayed relatively close.


 * Hisoka's Bungee Gum [Transmutation] - Normal people are unable to see it and it always is physically connected to Hisoka. Furthermore, it is not solid, but rather pure aura energy copying the properties of rubber and gum.
 * Razor's 14 Devils [Emission] - They were not solid and ordinary people couldn't see them. Razor's 14 Devils were pure aura, and they did not need to physically stay in contact with him.

Exorcism
Just as how Nen can be used to curse others, those curses can also be removed through the use of Nen. Those who possess the ability to do so are called Exorcists, but are rare among Nen users. There are fewer than ten people in the entire world whom are powerful enough to exorcise Nen curses left behind by the dead.
 * Notable Exorcists Include
 * ​Abengane
 * Hina
 * Alluka Zoldyck

Advanced Techniques
These are the more advanced techniques. Most of them are achieved by using a combination of the basic techniques. Most nen users learn Ten, Zetsu and Ren first before attempting these techniques. The Hatsu, being a nen-user's individual 'skill', is often something that a nen-user will develop gradually over a long period of time.

Shū
Shū (周 Enfold) is the advanced form of Ten. Shū allows a Nen-user to extend their aura to an object, allowing them to "use" that object as if it were an extension of their own body. For example, one could use Shū to extend their Ten around an object (and not just their body), which would strengthen and protect the object like the way Ren strengthens and protects the body. This is the technique that allows Hisoka to make his solitaire cards as sharp and as hard as metal knives.

En
En (圓 Circle) is an advanced application of Ren and Ten. In Ren, aura usually envelops only a small amount of space around the user's body. En is when one extends their Ren so that their aura extends further than normal, then uses Ten at the same time to give shape to the aura, usually a sphere. Someone using En can feel the shape and movement of anything entering their En-covered area. The downside to this is that it is extremely tiring and draining for the nen-user to constantly deploy so much aura. Those who master En are typically able to extend their En to a circle of 50m radius. There are exceptions--Zeno Zoldyck, one of the most powerful assassins alive, is able to extend his En to a radius of 300m. Also, the chimera ant Neferpitou, has an irregularly shaped En and can extend a tendril of it up to two miles away.

Ken
Ken (堅 Fortify) is the advanced version of the basic Ren technique. Ken is a defensive technique where a Nen-user maintains a state of Ren over their entire body, allowing them to defend against attacks from any direction without the need to use Gyō (described below). Ken is as useful as a defensive position, but is tiring to maintain. Additionally, it is not as strong as Gyō on any given part of the body, since it protects the whole body evenly. Because of that, it is used to guard when one wants to be cautious.

In
In (隱 Conceal) is an advanced form of Zetsu that can almost completely hide a Nen-user. In can also be used on a Nen-user's Hatsu ability to make it invisible to other nen users. The In used to conceal an ability or aura means that others will not be able to 'sense' the Nen being used. In can be countered by using Gyō on the eyes, or by using the technique En.

Gyō
Gyō (凝 Focus) is a technique where a Nen-user concentrates a larger than normal portion of their aura into one specific body part. This ability to concentrate the aura is known as Gyō. Gyō increases the strength of that one body part, but leaves the rest of your body more vulnerable.

Gyō is most often used on the eyes, which allows a Nen-user to see things which would otherwise be hidden (e.g. Nen objects hidden by In). This also allows a Nen-user to analyze an opponent to find weaknesses that would otherwise be unnoticeable.

Kō
Kō (硬 Temper) is a stronger form of Gyō, in which all of an individual's Nen-energy is concentrated into one particular body part. Zetsu is used to completely stop the flow of Nen in all other parts of the body. This makes that one body part exceptionally powerful, but leaves the rest of the body completely unprotected. This is used by some Nen-users as an offensive technique (a Kō-punch would carry all 100% of your Nen-power with it), but it is a risky move (leaving the rest of your body unprotected in a fight against another Nen-user is not generally a good idea).

Ryū
Ryū (流 Flow) is the term for real-time use of Gyō (adjustment of aura concentration in various body parts) by a Nen-user in battle. For example, the use of Gyō to increase the amount of Nen in a fist as one strikes with it, to increase damage done; or to increase the amount of Nen in an arm as it is used to block a blow, for extra defense.

nen

nen nen 念能力