Mystic Eyes of Death Perception

The Mystic Eyes of Death Perception (直死の魔眼) are a type of Mystic Eyes that are considered to be such a rarity that they are thought not to exist at all. They are possessed by Shiki Tohno and Shiki Ryougi, and Michael Roa Valdamjong in the body of SHIKI Tohno displays a similar ability.

Workings
The Mystic Eyes of Death Perception can be called a circuit that opens up in the brain and eyes to allow the user to "perceive death", the conceptual "Death of an Existence", as visual signals in the form of Lines of Death (死の線) and Points of Death (死の点). Their usage is not entirely dependent on the eyes of the user, as they can still "see" lines should they go blind or gouge them out. Rather than "seeing", it is more like they are "observing" everything at a higher level. They are invisible to normal people, only accessed through perceiving the natural flaws with overly strong spiritual sight by looking through channels that normal people cannot perceive. In perceiving death, it can be said they see the Root itself. They are similar to the eyes possessed by the Celtic god,, which were able to actualize death simply by looking, and they have not been possessed by anyone else since then.

The ability to perceive the death of a being or object depends entirely upon the user's perception of death. The brain and the Mystic Eyes work as a set, so having different "specs" allows for great differences in the users' abilities to perceive death. They show the death of things, the weak points where everything is most easily broken and the imperfection in everything that will break down one day. They can be said to see the fate of all things, seeing the future, allowing them to see death. While there is a difference as to when an person or object will "end", it is certain that they will all arrive at that point because death is not something that "arrives", but rather is something already contained within an object at its creation and certainly bound to happen as part of the principle of causality.

Anything with an origin must have an end, a "time of death" determined at the beginning, and as it already exists, it is not impossible to comprehend such a concept with the appropriate circuit in the eyes and brain, allowing them to be viewed as though through a microscope. It is normal that cutting a living being's neck would kill them, their life stopping because it was cut, and conversely not being able to cut a being's neck would mean that they will not die. The eyes can ignore the cause, instead allowing them to kill even that which is immune to all external effects. That which is cut falls apart and that which is "killed" becomes "dead", but rather than "tracing the lines causing the object to fall apart" and the object becoming dead because it was cut, it is "ending the lifespan and killing the object." It is the erasure of existence rather than physical destruction, so the object is "stopped" and the cut is the end result.

While Tohno's eyes are normally gray, they glow with blue while utilizing the Mystic Eyes of Death Perception. Ryougi's eye color is shown to become blue when utilizing the ability, but they are always active despite seeming to turn on and off.

Lines
Death emerges to the surface of an existence as lines, and cutting along them will result in "Death", regardless of the constitution or properties of the object. They have no particular structure, so the can be described as solid, black "zigzagging scribbles" all over the world, even within the air itself, that look like cracks. They are harder to see during the day due to the light, but emit a sort of glow at night. The lines of a living organism will keep changing position as long as it is alive, and those Ryougi perceives are constantly moving and irregular. They can be traced with any sort of object, effectively "breaking" the person or object along the line, cleanly cutting it without any need for force. The object tracing the lines "sinks into it", and although a finger will fit into the thicker parts, thinner objects like rulers or knives are more effective. Tohno does not attempt to actually trace lines with his fingers, and Ryougi breaks her finger while tracing along the line of a corpse possessed by a Wraith. While anything can be cut, the user has no say in where they can cut, as it depends on the placement of the lines.

Arcueid Brunestud theorizes that the lines are something like the weakest parts of the joints between molecules in an object or a predesignated switch within the genetic makeup that activates the death of the object. Those of Tohno are described as "lines where the substance breaks easily", while those of Ryougi are described as the "the concept of longevity given form" rather than lines at which "an object can be easily cut apart." Completing a cut makes it impossible to heal under normal circumstances, but Arcueid does manage to heal from a partial cut. The lines that are cut cause the corresponding part to die, making them never able to move again even if the main body is alive. While Nrvnqsr Chaos normally just reforms his body from his chaos, he cannot regenerate his arm after Tohno cuts it off. While Arcueid is cut into numerous pieces from having her lines traced, she manages to regenerate by completely reinventing the conceptual structure of her body, abandoning the conceptual structure that had been traced. Ryougi cuts off her own arm, but it is able to be replaced by a puppet arm.

Beings will have different amounts of lines depending on their complexity. Humans will have a countable amount in geometric patterns. The Dead have numerous lines all over their bodies that make their appearance hard to discern. Members of the Phantasmal Species will have very few "parts vulnerable to death." Those without physical bodies like Servants are also able to be killed.

Points
Points of Death are from where all lines seem to flow, resembling blood vessels. There can be a number of them on an object, and, whereas the lines are "where things die easily", the points are "death itself." The eyes do not actually kill "the body", as the power of killing someone's life is very common in the world. The "points" seen by the eyes end the very meaning, the "existence", of whatever is "killed." The destruction, the extinguishing of life that comes afterward, is only a side effect of destroying their existence. Striking the point makes the entity completely cease to function. What "makes a living person a living person" or what "makes a hallway a hallway" is ended in the simplest way, unraveling its existence and making it no more. This makes it possible to kill the soul without harming the body, allowing for the destruction of one of two souls in a single body without the death of the other soul or the body itself. The weaker soul is the one that will be ended, so it is a battle of strength in that case.

Points can be pierced by sharp objects. Piercing a point effectively “erases” that object from existence, causing the entity to completely cease in function. It can stop certain inherent properties such as momentum, toxicity, and generally any effect it may impose on it's surrounding. Disease, poison, and corruption like that of being turned into a Dead Apostle can be completely negated. Living things whose point was pierced get “stopped” and, as a consequence, die. Those who have accumulated an exceptionally large weight of existence take longer to die because there is more of their existence that needs to unravel. It is absolutely permanent, and can't be reversed or bypassed, even by Michael Roa Valdamjong's system that allowed him to be reincarnated seventeen times over eight hundred years.

Limitations
The ability to kill something with the eyes requires the user to actually strike the target, so those physically above the user will easily be able to avoid them with little worry. While Tohno kills Arcueid at her full available power with a perfect sneak attack, she would be able to easily avoid him if he were to actively attack her even in her drastically weakened state. There are also existences that are hard or impossible to kill due to their nature. Souren Araya's Sarira cannot be killed normally because it belonged to an enlightened one who achieved "becoming extinguished, alive." While it would be possible to see its lines of death, it would mean deciphering "advanced lines of death" levels higher than the normal concept of death.

There are those without true form like Night of Wallachia right before it takes shape. Something "made of words" and "which has yet to exist" cannot be "killed." Wallachia also can be called a "phenomenon" like "wind storms" and "typhoons", and while individual events of such phenomenon can be dispersed, it is impossible to outright kill the phenomenon itself. Ryougi works off of the notion of killing what she perceives as alive, so while she claims to be able to kill God "as long as it's alive", she can do nothing to God because "God isn't alive or dead."

There are also those who lack an actual death, such as True Ancestors during the night, especially under the full moon. While lines and points can be seen on True Ancestors during the daytime, they are too close to being "perfect life" during the night that they don't even carry the concept of death. After she has "lost her immortality" due to being killed, Tohno can see thin lines on Arcueid during the night. Through enough strain, Tohno is able to see a single line while after she has recovered somewhat, and cutting her off from nature allows for him to see even more. Against Archetype: Earth, Ryougi cannot see her death, and she goes as far to say that she doesn't have a death at all. Beings like Type Mercury and other Aristoteles lack the concept of death entirely, so the ability will not affect them under any circumstance.

Acquisition
Mystic Eyes of Death Perception are a hybrid power, taking aspects of both Mystic Eyes and Pure Eyes, but they are classified as ESP. They are acquired through a near-death experience, gained by being immersed in "death." Their frequency is so rare that they are thought of as nothing more than a myth even by beings like True Ancestors. Simply encountering them makes Arcueid Brunestud call Shiki Tohno a monster due to their unique attributes not found even among the most powerful creatures on the planet. While the user can still perceive death without the eyes, Touko Aozaki would still pay any price to obtain them. The eyes can be thought of as more special than those possessed by any other user of supernatural power in the world, eyes that can kill anything just like death itself.

Tohno acquired the eyes after being essentially killed by SHIKI Tohno and immediately sustained by Akiha Tohno's life force. Ryougi acquired the eyes after a two year coma left her in contact with the Root for a prolonged amount of time due to being hit by a car and the "death" of her male personality. Arcueid believes Tohno had a natural affinity beforehand, and as part of her third personality's abilities, Ryougi's body already had the ability to see them. The ability was simply brought to the forefront and awakened by the accident.

Differences
The eyes of Tohno, Ryougi, and SHIKI have difference usages and limitations.

Shiki Tohno
Shiki Tohno specializes in killing living things. Unlike Ryougi, he is not suited in the aspect of recognizing "concepts" because he was "submerged in death" rather than touching the Root. He can perceive the death of concrete physical existences, allowing him to kill people, animals, locks, walls, and even part of the planet itself in the form of killing "nature" in a specific area. He cannot see lines on things that are unable to be killed or destroyed in the current world because the standard for Shiki, as a human, is based on the limits of the people of his era.

He has a great deal of mental strain when utilizing his ability. Due to performing the normally impossible process of his brain classifying the death of non-living objects, it overloads his brain because "seeing" requires "comprehending." His brain must open its circuits from the classification of living things to the classification of non-living things to see the death of non-living objects. He, as a living being, cannot comprehend the death of inanimate objects, so he must connect to a circuit with the same orientation as them. He will be fine as long as he only perceives what he brain allows him to perceive. Overuse of trying to perceive the death of what his brain will not allow him to normally perceive will eventually overstrain it, causing the blood vessels in his brain to burst and end his life. Overuse without going over his limit can lead to extreme headaches and even temporary loss of sight.

Beings do not have to have "life" in order to be "killed", so even The Dead without life can be slain. He can stop anything that can move and break without exception. While he cannot normally kill concepts, he can see certain things like Akiha Tohno's Caging Hair due to the Mystic Eyes' second nature as Pure Eyes. He has a hard time perceiving the death of Nrvnqsr Chaos, as he can only see the individual points of death for his beasts. He realizes he would have to kill each individual point in order to end him, but eventually manages to see an "Ultimate Point" below all the others deep in the center of Nrvnqsr's being.

Shiki's eyes are constantly developing, and he becomes more in-tune with death the more he utilizes them, bringing himself even closer to death as well. He originally can not see the "points", but starts seeing them more and more after his encounter with Arcueid. He can initially only see the points on living things, while all other objects only have lines. He begins to see points on them with great strain, causing him to pass out, but eventually becomes accustomed to them as well. He will see the lines even if he does not will himself to, but to see the point from where the lines flow, he needs extreme concentration. He utilizes Mystic Eye Killers, glasses made by Touko Aozaki and reinforced by Aoko Aozaki, to keep them from being active, but there are times when even they are not enough to keep him from seeing the lines as he uses them more often. He is shown utilizing some kind of cloth bandage in Talk. rather than his glasses, and it is unknown if it has any special properties.

Shiki Ryougi
Shiki Ryougi specializes in killing concepts because she touched the Root and became specialized in the visualization of events. She does not see the Points of Death, but the Lines of Death she sees appear to function in the same manner. She is a Mystic Eyes of Death Perception user several ranks above Tohno. She is able to perceive the death of mostly anything, though it is limited to what she perceives as "alive." Something like a telephone is seen as "being alive because it's not broken", so she will not see lines on a broken telephone because she feels that it is "already dead." The notion only refers to her perception of "living" rather than if it has "life", so Kirie Fujou's ghosts can be killed even though they are "dead" because they are "living" in the sense that they can interfere with the current world.

Differing from Tohno, she doesn't show any noticeable strain, allowing her to actively utilize them as much as she wishes. She can kill things with form like people, objects, and spiritual bodies, and she can kill concepts without life or form like diseases, ESP, magecraft, Bounded Fields, or anything else of the sort. She is even able to kill the "future" predicted by Mitsuru Kamekura, causing his clear vision of it to be bisected and disappear. The reason is that it was not a prediction, which she would not have been able to see, but a clear calculation exceeding prediction. Coincidence cannot be reached out to, but it is possible to reach out to a certainty. The future is normally invincible because it is uncertain, but giving it clear form allows it to break. That which is determined is no longer the unknown, so it having form allows for the concept of death to be applied to it. It is a clearer "killable" target to her than Fujino Asagami's ESP.

As a living being, she has an easier time seeing the end of another living being, as it is easier to comprehend "the death of a living being." Seeing Lines of Death on minerals or concepts requires her to become minerals or use her brain and tap into her "imagination." She does show some mental strain while trying to perceive death on Souren Araya due to his Origin and the Sarira in his arm, but he believes she would overcome even those with time. The initial lines are faint, and he has a line spiraling at a single point on his chest that looks like a hole. He notes that she can cut off the root of motion on anything alive or dead as long as it has that motion. Even he, who is a stopped organism, must have a thread that permits his existence as long as he actually continues to exist, and he believes that even the unique exception of the Sarira cannot be hidden from her forever.

SHIKI Tohno
Those possessed by Michael Roa Valdamjong in the body of SHIKI Tohno cannot be called true Mystic Eyes of Death Perception. They can be called similar and completely different at the same time. While he can see the same lines and similar points, he can only view the "life force" in living beings. He is not seeing their death, and he also cannot see the death of inanimate objects. They are limited to directly damaging or annihilate someone's life force, the "place indicating the source of life" and the "part which keeps things alive." They do not kill outright by actualizing death, but instead inflict critical damage on someone's life force that leads to their death,