|English anime||Fighter's Will|
|Appears in||Anime, Manga, Game|
This technique was inspired and forged by the amount of will power users place behind their physical blows. Those who specialize in taijutsu have learned to harness this willpower and translate it into a nearly invisible physical aura which allows them to extend the range of their Taijutsu and Kenjutsu considerably. This increases the danger for those who are not skilled at close ranged combat, for an attack could seemingly "miss" but the aura can still deal damage, albeit at a lower level than usual. Those who have mastered the art of taijutsu have their blows extended even farther, at nearly three times the average distance, making them even more dangerous. The damage that the aura itself deals is weakened the farther away from the user it is, being closest to the user's own damage output at the very center, to almost non-existent when extending any distance above 5ft. However, a skilled practitioner of aura is still able to use it to their advantage.
Being an extension of their willpower, Aura has several added effects dependent upon the strength of the user's will. When the user has been beaten badly in battle, but still have the will to fight on, their aura will turn a color that represents the user best, the most common being a blood red color. With this change in their aura, they enter a state known as Aura Rage (霊気怒り, Reiki Ikari), granting the user a minor second wind and numbing any pain they may be feeling in order to strike down their enemy. Their aura extends to 10ft and now deals two times the user's damage at the center and decaying to as low as half the user's damage at the very edge. This state can be held for no more than fifteen minutes, but will end as soon as the user strikes down the person that had injured them enough to activate this state. When it ends, the user will feel extremely drained and fall unconscious almost immediately.
There is a secondary function, though it requires the death of the user. After being mortally wounded, or achieving a level of rage that brokers immediate vengeance, the user pours all of their life force into their Aura in order to turn it into a separate entity known as an Aura Memento (霊気記念碑, Reiki Kinenhi), though they die in the process. This entity is immune to nearly all kinds of damage, namely chakra and physical attacks with moderate resistance to Natural Energy, and is nearly indestructible. Said entity takes the form of the user in the shape of an agent of vengeance, taking the form of a monstrous demon or a glorious angel at the discretion of the user. This entity will follow whomever forced the user into this state for all eternity, never giving up its hunt until the offender is dead and in the grave. Once this is achieved, the entity will fade out of existence with its purpose being fulfilled.