Nen
Nen is the ability to manipulate your own life force to a potential not averagely achieved by humans. It will become the defining part with your character creating abilities and powers. All information is gathered from
Here with some additions for balancing purposes and such. It is mostly repasted here for your convenience.
Creation and Use
Nen teaches one to control their own aura flow and utilize the energy.
Aura is the life energy produced by all living bodies vital for survival. 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, typically resulting in a slow leak of aura continually escaping the body. If one were to lose their entire aura, it would be equivalent to using up all the energy keeping them alive, which would be fatal. The pores or points on the body from which aura flows out from are called "Aura Nodes (精孔, しょうこう) shōkō)." Controlling those nodes is the first step to being a user of Nen.
Learning to use Nen is the final step in becoming a professional Hunter because most contracted jobs require the use of it as the minimum requirement. The technique has the ability to enhance the strength of physical attacks or objects depending on the quantity of aura employed and an individual's aura type, as well as allows for para-psychological abilities to exist in reality. Because one can craft just about any sort of psychic power through only using their mind, Nen is also a dangerous power unknown to the public at large.
Learning Nen and Initiation
A student learning Nen trains to manually open and close their aura nodes so that they can control the flow of their aura. One typically learns this process slowly and gradually through meditation. The second method (colloquially called Initiation or Baptism) 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 if the user is inexperienced or has malicious intent. Initiation via physically attacking another with the use of an enhanced aura typically causes permanent disability or death.
There is, however, a way to initiate that is less harmful to the student's body — depending on gently jolting open one's 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, he will be able to see his own aura as a shroud surrounding the body due to his nodes in his eyes being opened. Aura appears to look similar to steam from a kettle.
It is possible to feel the presence of aura even without being aware of its existence. It has been described as feeling like a warm, viscous fluid at rest. It has been said that powerful, refined auras produce a sensation that feels akin to needles pricking into the skin. Since every living being emits aura subconsciously, learning to sense aura is a useful skill for those tracking living things or hunting non-living things infused with aura. An experienced user of Nen can judge the location and relative strength of his opponents through reading the output of their aura.
Nen and Emotion
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, and 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. blood-lust). The antagonized will then be able to feel that blood-lust as if it were physically palpable; if unable to keep it from their own body by deploying their own Nen, he/she may be physically harmed by it.
Vows & Limitations
Being a product of the mind, Nen responds to the goals, strengths, and desires of individual users. As a result, a student of Nen can increase the overall power of an individual skill by stating a self-imposed restriction that forces even more conditions on it. For example, if one 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 manages to abide by that rule, that particular skill will become stronger. These conditions are called "Vows (制約, Seiyaku)" or "Contracts". The stricter the Vow, the more one's own ability is strengthened. It is also implied that Vows that carry great meaning or are tied to emotional states also bring about a greater benefit. However, Vows are also considered liabilities, since breaking a Vow carries the risk of completely obliterating one's own Nen abilities.
Vows that contain some sort of punishment (i.e. "I will die if I break this rule") will strengthen the ability even further. These are called "Limitations (誓約, Seiyaku)"—covenants to oneself
