Yoki aura

The Yoki Aura is an aura emitted by anything possessing yoki. Anything with a yoki-aura possesses yoki-perception, even it is to a dismissal degree. The yoki aura of an individual is unique and can be revealing of their personality, age, seasoning, state of mind, and even form in the case of awakened beings. Yoki auras are one way to quickly gauge the strength of an opponent, the greater the aura's quality (and to a lesser extent, quantity), the stronger the opponent. Abyssal ones have a crushing feeling emitted from their aura, the abyssal aura.  
The aura of a being can be synced with by another yoki-user to perform techniques on them, be it healing, destructive or manipulative in nature. Intense yoki can manifest an aura visible to the naked eye, even to a human with no yoki-perception.
Yoki aura is detected by a being's perception, a sixth sense all yoki-users have. Each being has a unique way of using perception and varying degrees of competency sensing. For all animal-based yoki-users, perception exists as an extension of one of the 5 senses. Although all senses of a being are sharpened with yoki, one dominant sense becomes a being's way of interpreting a yoki aura. For most beings, yoki perception manifests itself through sight, with users being able to see auras like stars in the dark. However, yoki perception can also manifest in the other senses, although this is far rarer as sight is by far the most dominant sense. When yoki perception manifests through hearing, the user hears yoki as sounds unique to each source (23). Manifesting through smell, the user can find sources of yoki through smelling their scents and obtaining information through the scent (Lenora, Brook). Manifesting through taste, a user can sense yoki in object's contacting the tongue or thick scents that can be "tasted". Yoki detection through touch enables a user to see a being's aura through physical contact and experience physical sensations on their bodies when a source of yoki is detected, according to Iris, through an unpleasant feeling of cold (Medea, Grace). A being can possess multiple types of perceptions, although only one dominant type. Humans also can possess perception, called sixth sense, which gives them a feeling or natural avoidance (or attraction) to yoki. This type of perception can detect even a yoki-using being that has completely hidden its aura like a Vanguard. 
Yoki aura is sometimes used for intimidation. Aura can be used as a scare tactic for awakened and yoma to chase away threats or territorial disputes as yoki aura usually can be used as a way to determine the strength of a yoki-user. This applies to both the quality and quantity of the user, a stronger user usually having more of both.
Yoki aura is naturally tied to heartbeats. The more heartbeats per minute, the greater the aura. A more unconventional way of sensing yoki is to search for heartbeats rather than an aura. A being cannot have no heartbeats or it would be dead. Beings that hide their yoki perfectly still can be found with this method. Heartbeats can be used to create pulses of yoki that for Abyssal Ones or stronger, can seriously damage opponents. 
Most beings with a yoki-aura can't erase their aura, only suppress it and hide it. Abyssal ones can slow down their "heartbeat" to emit only as much aura as a double digit. Beings that have their souls (observer) combined with yoki are able to truly hide their aura by emitting nothing since there is no "fight" between the will of the yoki and the soul's will. The true reason a conflict of wills creates a yoki aura is the wills' desire power over the other will, and the rejection of the other will's being. This hatred causes separation between the mind and soul and the yoki and creates a yoki aura. An alternative way of thinking about them is to realize that such beings aren't truly existent in reality (as they exist entirely in the void as yoki), and thus, can choose to reveal themselves on a lower dimension (reality) while most beings still have a component of reality inside of them that remains unmerged with the yoki, forcing the yoki into existence and revealing their presence constantly. Beings that have combined souls and yoki can control how much of their aura to show, even while fighting, regardless of the number of heartbeats.
Grace emits no yoki aura whatsoever, no matter how much yoki she uses. Although Grace never chained her yoki, her lack of aura likely comes from her pure drach nature, which never have auras, and not from the fact that there is a lack of conflict between Grace and her yoki's (Aezathol) will. Grace's being appears to also suck everything into itself, possibly the reason why no aura can be emitted from her. 
Naturally born hybrids possess auras which appear to be halos. Zeros possess a convoluted, inky aura which appears to cover their figure. Ascended angels can hide their auras entirely. Awakened ascended angels have auras that appear as a mix of claymore and awakened auras. Colorheads appear differently aura-wise than regular awakened or claymores. Most beings appear as lights/stars in the dark, usually blue colored, although a more accomplished sensor can determine each of these star's particular "textures" and sizes, which give more information about the particular shade.Category:Terminology