Aura

Utilization
There are two primary means of utilizing aura: Reinforcement and Manifestation.

Reinforcement is the art of directing the aura's effects first through a physical medium, giving it preternatural characteristics before the aura shows itself directly if the strength of the warrior's aura is sufficient (the Estebans tend to channel it into their bodies first, which may or may not have something to do with their incredible physical traits). Donape Asylan is described as having taken this aspect to its uttermost end, being the basis of his claim to being the best warrior (ch. 178).

Manifestation is where the aura is outputted directly beyond the person, giving it shape and enabling it to be utilized without potentially harming a medium. An example from the current time of the story is Raphaello Cheringer, who manifests his aura as a skill called "Ring".

Though Reinforce and Manifest are the primary means of aura utilization, no two people use aura quite the same way due to its utterly unique nature, nor are they the only ways to use aura. Swan Katarina uses a different method known as accumulate, which appears to be a development of how certain aura users can store aura within a physical medium for an undefined amount of time.

Others
Demons

Swordsman-> Sword Qi

Warrior -> Aura

Magic Swordsman -> Magic + Sword Qi

skills
Aura Barrier (ch.87)

Aura Qi (ch.105)

Aura Form (ch.121)

Aura Blade (ch.123)

?

Ranks
Above King/Queen