Some enemies attack the body.
The Onmyōsha are trained for the ones that enter the mind.
The Onmyōsha are the suppressive, restrictive and corrective arm of the Innentō — specialists in ethereal containment, psychic severance and spiritual interdiction. Where the Yūnen-kai expands consciousness, the Onmyōsha exists to impose limits upon it.
One opens the mind.
The other decides when it must be closed.
Their operatives are not conventional soldiers.
Their battlefield is rarely visible. It exists between memory and identity, where foreign intelligence can hide behind familiar thoughts and corruption can wear the face of the person it is consuming.
An Onmyōsha does not merely ask whether a subject is alive.
Who is still alive inside them?
Their doctrine begins with a dangerous truth.
Any mind capable of reaching beyond ordinary human perception can also be reached in return.
The Onmyōsha do not condemn extraordinary ability. They condemn power used without restraint, discipline or protection.
Their work is therefore built around four principles:
Dampening.
Severance.
Fortification.
Termination.
Dampening reduces dangerous psychic activity without destroying the subject’s abilities.
Severance is more invasive. When an external presence has attached itself to a host, the Onmyōsha attempts to identify the connection and cut it away before the invading intelligence takes complete control.
Mental fortification prevents corruption before it begins.
Termination is reserved for the point beyond recovery.
The difficulty is knowing when that point has been reached.
Ethereal corruption does not always announce itself with mutation or madness.
It can begin quietly.
The possessed may appear rational.
The corrupted may believe themselves enlightened.
The dying personality may defend the thing consuming it.
For this reason, Onmyōsha training is brutal.
Candidates must learn to distinguish their own thoughts from intrusion, endure psychic pressure and recognise when emotion has been manipulated from outside. Fear, grief and desire are not weaknesses to be erased.
They are vulnerabilities to be understood.
The goal is not to become emotionless.
It is to know when an emotion no longer belongs to you.
This also defines their uneasy relationship with the Yūnen-kai.
The Yūnen-kai pushes consciousness outward.
The Onmyōsha stands behind it with the blade.
The two orders may fight beside one another, trust one another and even depend upon one another.
But every Yūnen-kai practitioner knows the truth:
Their Onmyōsha counterpart may one day be ordered to kill them.
That is not betrayal.
It is the Innentō’s idea of balance.
The Onmyōsha does not seek mastery over the unseen.
It exists to prevent the unseen from mastering humanity.
Its entire doctrine can be reduced to one principle:
The mind may command power.
Power must never command the mind.