Agin Ki (アギン気), also known as Death Ki (デス・キ) or Anti-Ki (アンチキ) and can be viewed as, "Death Force Energy" is the anti form of Ki found in the Alterverse.
Agin Ki is the tangible manifestation of energy for those residing within the Yin Realm. Similar to that of normal Ki, Agin Ki works as a way to increase an individuals fighting potential by either drawing it out or using it to amplify their abilities. As a form of Ki, it's stored within the soul of it creator/user and can be brought out when the time arises.
The greater amount of ones energy, the more time is required to draw it out to it's full potential. Agin-Ki us used to enhance ones strength, speed, endurance, and can increase the damage inflicted onto their opponents.
In most cases the body isn't capable of handling all of their energy and thusly limits its usage. The same can be said about how one draws out their power, without a powerful mind one can't draw out this energy. Through training both of these issues can be overcome. By maintaining balance between once body and mind the soul is also capable of creating a surplus of Agin-Ki.
If the body becomes damaged then Agin-Ki can leak through these injuries, the more major the injury the greater the lot of Agin-Ki. If ones mind becomes disturbed or hindered in any way then their control can become impaired, if they forcibly use their Agin-Ki in this state then it can run rampant and uncontrolled.
Agin-Ki can be divided up into three main sub-energies:
- Genki; Energy generated passively through possessing a Soul
- Anti-Yūki; Energy generated passively through using a Body native to the Yin Realm
- Anti-Shōki; Energy generated passively through using a Mind native to the Yin Realm
Due to the effects of LAW Agin-Ki behaves similarly to anti-matter, creating parallels between the two. Genki has been viewed as the neutron, Anti-Yūki as the antiproton and Anti-Shōki as the positron. While similar is concept they're vastly different in practice.
(To Be Added)
Agin-Ki is normally imperceptible to the naked eye, however, highly concentrated amounts can be seen. The color of ones energy varies from individual to individual, the most common color being black but it can vary from anywhere on the visible spectrum. Unlike normal Ki, those of a corrupt heart have a white aura rather than black. This color also varies depending on a technique or transformation being used.
Agin-Ki users can be identified by their ever present Black Halo found above their head.
An aura is generated by a user bringing forth their power. Their aura can be used to power up their natural abilities and skills, the more concentrated, the more potent. Some techniques can double ones aura, creating two distinctly different aura at once, though this is rare. At a certain level the Anti-Shōki of the user will become erratic and at times roam independent of the aura, this is represented by sparks or flashes of lightning, this is sometimes referred to as Plasma-Auras.
One can't speak of Agin-Ki without first understanding it's origins and by extension, Soul Decay. Agin-ki isn't a separate source of energy that someone can tap into, as is the case with God Ki. A single being can't wield both normal Ki and Agin-Ki simultaneously as these two energies are contradictory and would corrode the user before they could use either one.
Soul Decay is a natural process that occurs to the soul of every living being. From the moment a soul is created it begins to slowly decay, the longer a soul is around the faster this process becomes. The amount of ones Ki also effects the decaying process. The less Ki one has the longer it takes for ones Soul to decay. The process is also known for slowing down a person's Ki cultivation as well as their ability to contain that Ki.
While this is a terrifying premise, this process takes place over a thousand life times and the choices of one reincarnation hardly has an effect on the overall process with some exceptions. As I mentioned before, in most cases Soul Decay will result in that soul being erased from existence, but this isn't always the case. If a being can withstand the transition from normal Ki to Akin-Ki they enter a new state of being, Death.
Keep in mind that those with Immortality aren't an exception to this law but are actually the most susceptible to it. When souls pass on to Other World they get cleansed of their Ki, slowing down the decay even further but this isn't true for Immortals as the artificial/magical extension of their life corrupts the soul even faster.
Agin-Ki and Ki go through this process equally within their respected realm.
(To Be Added)
When within the Yin Realm, Agin-Ki behaves as Ki normally does, however, this changes when it enters the Yang Realm. Here Agin-Ki enters a heightened state of Soul Decay due to the surplus of Yang Energy. This also seems to increase ones power exponentially, meaning that Agin-Ki users are actually vastly more powerful in the Yang Realm than those same users in the Yin Realm. This power-up is visually represented by their Aura as is becomes unstable, this kind of Aura is known as a Decaying Aura.
It's called this not only for the acceleration of Soul Decay but also for its decaying nature on the realm around them as flora and life begins to quickly erode away. If Agin-Ki were to come into contact with its natural counterpart they would simply eradicate each other out of existence, however, due to the Decaying Aura they have the advantage in a fight.
This advantage isn't always true against other types of Ki. Dense Ki, due to its inability to be affected by Ki less dense than itself has a higher tolerance to Agin-Ki, however due to still being Ki at it's core it too is afflicted by it's effects. God Ki is another example of Ki capable of resisting Agin's effects and while it may be more resilient than Dense Ki, it too isn't capable of overcoming its effects.
When Agin-Ki passes over into the Yang Realm it upsets the balance of the Alterverse and causes catastrophes across every Realm from Other World to the Dragon Realm. When the balance is upset beings known as Pillars will feel this disturbance and seek to correct it, with force if necessary. These effects will continue to last until the cause of these events are corrected.