Aura

Aura is the manifestation of our soul. It bears our burdens and shields our hearts.

Aura is the manifestation of the soul in the RWBY universe, which can be used for a wide range of abilities depending on the person and its practice in the use of it.

Description
Aura is an ability that all those with a soul can use, at least with enough practice. Because Aura is the manifestation of the soul, it can appear very differently depending on who is using it. For example, the color of Aura is different from person to person. Also, a person with a strong Aura may radiate brighter when using it.

It is mentioned that anything with a soul has an Aura, but humans seem to be the only beings able to weaponize it for their own protection. A skilled user of Aura can create barriers or even increase their abilities in some way. Weapons can also be made that act as a conduit for Aura, allowing for an even wider range of attack.

Abilities
Aura is a necessary energy source for all Hunters, being their most powerful ally when in battle. Aura, as demonstrated by various characters, has the ability to do the following:
 * Heightened Perception: Aura seems to be able to sharpen one's senses, or allow one to detect danger, as mentioned by Pyrrha.
 * Defense: Demonstrated by Ren in the forest, and explained by Pyrrha. The use of Aura is mainly for defensive purposes. Ren used his to block the fangs of a gigantic snake creature that was attacking him.
 * Offense: Demonstrated by Ren in the forest, as he sends a shock wave of force propelling a fang through the snake's head, causing it to explode. Additionally Pyrrha has stated that all tools and equipment are conduits for a person's Aura.
 * Unlock Aura: One's Aura can be used to 'unlock' the Aura of someone else, as shown by Pyrrha, who unlocks Jaune's Aura. Doing this appears to take a toll on the user however.
 * Healing: It seems that those with a strong enough Aura can heal own (minor?) wounds. Jaune used this directly on a small cut after having his Aura unlocked. It appears that the healing is automatic and not caused by urge.  To what extent, if any, Aura can be used to heal other's wounds is as of yet unknown.

Activation
It appears that Aura is able to manifest in different ways when in use and takes on the color of ones inner energy. It appears as a slight glow around the body and also seems to be able to change eye color in certain people.

It has been stated that the activation of an Aura requires training and willpower, though someone with considerable training can unlock the Aura of another person.

How the Aura manifests seems to vary from person to person, depending on their personality. Yang's Aura is shown to be powerful and bludgeoning because of her head strong personality, while Ren's is piercing and direct for his calm and serious one.

Known Aura Users

 * Lie Ren - Ren's Aura appears to be a shade of pink. His Aura allows him to make barriers and increase the force of his attacks. His pistols can also fire his Aura.
 * Pyrrha Nikos - So far Pyrrha has used her Aura to unlock Jaune's. Not much else is known about her Aura, but she is very knowledgeable about it. Her Aura is an intense red color.
 * Jaune Arc - After his Aura is unlocked, a cut on his cheek rapidly healed. It is unknown what else his Aura can do, but Pyrrha notices that he has a lot of it. His Aura is white in color.

Trivia

 * It is stated by Pyrrha that only those who have souls are able to use Aura, meaning that creatures of Grimm are unable to use this ability as they lack a soul and thus, an Aura.
 * People can have different colored Auras, possibly reflecting the type of soul they have. Pyrrha's looks red, Jaune's looks white, and Ren's appears to be a shade of pink.
 * It can be compared to Ki or Chi in other media.