Muramasa (Seireitou)

Muramasa (村正, "Village-Just") is the  entrusted to the  of. It was often held by the head of the family, but after an incident five hundred years ago, the Muramasa was thought to be lost before being recovered by. Due to its malicious nature, the Zanpakutō remains sealed within the Kuchiki compound.

Characteristics
An existence that has swayed many souls to the temptation of power and prestige that can only be promised by the shadows, the one known as Muramasa has cycled throughout many lifetimes as countless personages; it has turned brother against brother, child against clan, soldier against society, bringing about the ruins of that which we call mortality and decency itself. And with each time the spirit was passed on to its next handler, its nature continued to run rampant within all that it were to encounter, as if the spirit was driven by a deep-seated obsession to corrupt, bordering on pure lust.

History
According to legend, the Muramasa was forged after the Kuchiki clan ancestor attempted to seal the spirits of in an effort to pacify the realm and establish order. Due to how the was structured, Hell was a dimension connected to the world and its malicious essence was constantly flowing into the world, invoking the worst qualities of humanity that fell victim to its miasma. Therefore, it was deemed necessary to find a way to block off Hell from influencing the world of humans. In the process, a sword was created to contain the malevolent nature of Hell that was sealed within it, and held by the Kuchiki clan whose own reiatsu constantly imposed order onto the chaotic spirit within it. While the blade was held by Kuchiki leaders for several millennia, the Muramasa was lost at some point and thought to have fallen to the.

1501 AD. It is said that the first known blade forged by the swordsmith, Sengo Muramasa, was made at this date. And should this be true, it was here that all the blades forged by Sengo Muramasa were imbued with the power of the darkness spirit. All of his blades were cursed with a powerful blood-thirst that could only be appeased with the execution of many victims, and it is said that all of this returned to the swordsmith's own madness and obsession with creating an unrivaled blade. The spirit of Muramasa is one that drives others to madness, and as such, these blades forged by the human swordsmith were those that corrupted all swordsman that wielded them; kill or be killed, those that held a sword of Muramasa had only those options before them. And this eventually led to the shogun, Tokugawa Ieyasu, from banning the use of Muramasa's blades. He knew all too well the darkness that shrouded those blades, having lost many a comrade to those heinous weapons. With the eventual death of the swordsmith, the blade was eventually recovered during a mission to the world of the living by the, and returned to the Kuchiki clan.

When was the head of the Kuchiki clan, an incident occurred where one of the heirs to the family,, fell victim to the blade's conniving nature and became drunk on its power. When the situation was resolved, Ginrei opted to seal the Muramasa properly so that no Kuchiki would ever fall victim to its evil again. As such, it now remains sealed underneath the Kuchiki compound.

Powers
Curse: Like all held by the, Muramasa is also a cursed sword which indiscriminately rouses the darkest instincts and emotions within its wielder and all those around it, driving them mad until they lose their heart and mind to its darkness. While those of a sufficiently powerful can stave off the sword's influence, it is thought that only the unique nature of the reiatsu held by Kuchiki clansmen which imposes order onto the surroundings can properly pacify the sword without suffering to its effects.

Released Form: As a Zanpakutō which was sealed in order to contain its malice, its power can be awakened by the command "Whisper" (囁け, Sasayake). When released, the blade itself remains uncharged, but a potent and malevolent reiatsu coats its wielder and starts to latch onto the surroundings. The longer it remains in its released state, the further its influence reaches, eventually reaching a point where the Muramasa can potentially affect the entirety of the Soul Society if left unattended. Portions of Muramasa's power can escape its seal even without its release command being spoken.

Zanpakutō Control: Muramasa possesses the power to freely control the spirits of other. When its ability is invoked, it rouses the primal instincts of the Zanpakutō spirit and causes them to turn on their wielders. In doing so, the spirit is forced out of its wielder's inner world and permitted an existence of their own outside of their. However, the power of Muramasa is not limited solely to Zanpakutō but can also be used on any spirit, allowing the wielder to stir the darkness in the hearts of any individual; regardless of their nature. once theorized that if the power of Muramasa was excessively administered to the heart of a soul, it could even force them into. It can also control the souls of lesser creatures with ease, such as, allowing the wielder to tame and command them as they see fit. The only way to counter its power and thus resist its influence is to close off one's own heart, for Muramasa's ability works by intruding into the hearts of its victims.


 * Indirect Invocation: Those who are under the control of Muramasa can have their powers and abilities indirectly accessed by the Zanpakutō. It becomes possible for the sword to direct the actions of those under its control, as if the ability they wield belonged to Muramasa.


 * Spiritual Absorption: Given that Muramasa can control spirits and that particles are the fragments of souls long since past, it is possible for the Zanpakutō to absorb reishi in order to fuel its own . Similarly, Muramasa can absorb the reiryoku of souls that fall victim to its influence. The end result is that Muramasa is a Zanpakutō that can infinitely restore its own spirit energy through alternate sources. However, unlike the  which can manipulate reishi, it can only absorb for the purpose of fueling its own soul.


 * Yūkōjōchū Muramasa (有鉤条虫村正, "Hooked Tapeworm Village-Just"): When Muramasa invades the heart of its victims, in reality, what is happening is that a parasitic relationship between its own soul and the soul of the victim is being established. In a sense, it is as if Muramasa latches itself onto their hearts and provides a steady flow of its malicious reiatsu into the victim. It is likened to that of a tapeworm. Because of this, so long as the Zanpakutō continues to provide that source of reiatsu, the influenced spirit can maintain its independence outside of its wielder. When this connection is forged, a copy of Muramasa exists within the victim's own inner world, and enables him to interact with the victim as a result. Through this connection, Muramasa, and its wielder, can teleport wherever Muramasa's influence exists; even across dimensions.


 * Hypnosis: As an extension of its power, Muramasa can impose a hypnosis onto its victims by controlling their senses. It does this by interfering with their comprehension and perception, invoking an effect resembling total control of all five senses, including . In doing so, Muramasa can create lifelike illusions that are almost impossible to distinguish from reality.


 * Shadow Threads: Muramasa, as a spirit which can control spirits and rouse their darkness, can inherently seize control of a victim's shadow. It is a conceptual application of his power in which it creates threads through shadows in order to grab hold of the victim's own shadow, which imposes a paralysis onto them and renders them incapable of movement. While the threads themselves are invisible and intangible, they can be seen through the shadow or reflections they cast on the ground or surface between Muramasa and the victims. The only way to stop the paralysis is to disrupt the visual reflection, whether by destroying the surface below or causing ripples in its uniformity.

Behind the Scenes
After Bleach: Can't Fear Your Own World had canonized the existence of from the anime filler arc, the  chapter, the author took it upon himself to explore the concept from a renewed point of view. This article is the result of that endeavor and is based entirely on the ideas and preferences of the author.