There are six types of aura; every individual is born having one of these six different aura types. Upon learning one's own aura type, a student of Nen can set about learning to apply the technique 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. Divination requires one to float a leaf atop a glass of water. A student of Nen will place their hands around the glass and perform Ren. The resulting effect from one's aura contacting the glass will determine a person's aura type.
- If the volume of the water changes, the user is an Enhancer.
- If the taste of the water changes, the user is a Transmuter.
- If impurities appear in the water, the user is a Conjurer.
- 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 a completely different change appears, the user is a Specialist.
It is best to base a Nen ability on one's individual aura type. Though it is possible for one to develop abilities outside of his primary aura type, one is typically less proficient at using those abilities. By creating an ability that one isn't suited for, one risks stagnating their potential by overloading their capacity for using Nen —something called "Memory Overload."
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Enhancement
If a student increases the quantity of water in the glass during their water divination, they are an Enhancer (強化系, Kyōkakei). Enhancement is 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-ranged melee combat.
Enhancement is the most balanced category, allowing users to spread themselves evenly between offense and defense and become very strong using only simple abilities. One of the examples of more complex Enhancement abilities include enhancing one's healing factor.
Transmutation
If a student changes the taste of the water in the glass during their water divination, they are a Transmuter (変化系, Henkakei). 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 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.
Conjuration
If a student creates an object in the water in the glass during their water divination, they are a Conjurer (具現化系, Gugenkakei). 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.Conjuration is the only way in which Nen can create things that ordinary people (unaware of Nen) can see and touch. Furthermore, objects or entities created 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. Similar to Manipulation, Conjuration abilities tend to be very specific, complex, and conditional. Conditions can be imbued into conjured objects to make them stronger.
Emission
If a student changes the color of the water in the glass during their water divination, they are an Emitter (放出系, Hōshutsukei). 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.
Some Emission abilities are commonly mistaken for Conjuration abilities. The two, however, are fundamentally different. Objects created by Emitters are created solely from aura, invisible to those whom haven't learned Nen, and require Manipulation skills to control.
Manipulation
If a student moves the leaf floating on the water in the glass during their water divination, they are a Manipulator (操作系, Sōsakei). 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.
Specialization
If a student causes some other effect during their water divination, they are Specialist (特質系, Tokushitsukei). 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.[59] This is the vaguest Hatsu category. 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.
