This is what it means to kill something.
Age : 19
Shiki Tohno (้ ้ ๅฟ่ฒด, Tลno Shiki?) is a member of the Tohno household living in Misaki Town. He possesses the Mystic Eyes of Death Perception, Mystic Eyes that allow him to see "death." He is the main protagonist of Tsukihime and the Tsukihime series.
Shiki is a fairly normal high school student most of the time. Due to his close brush with death, he is not overly concerned about dying, and instead seeks to cherish every moment of his life - 'just living is enough' is his perspective on life. He is playful with his sister Akiha and the maids Hisui and Kohaku, sometimes silly, and not at all above exchanging jibes with his best friend and classmate Arihiko Inui or pleasantries with his senpai Ciel. He's entirely capable of being serious in a serious situation, and just as often flustered or embarrassed. His personality is one of that who is slightly mean to those he loves. He is also a very, very heavy sleeper, to such a point that Hisui is unable to awaken him.
Mystic Eyes of Death Perception :
Shiki's Mystic Eyes are a unique ability that allows the user to grasp the death of living beings as "points" and "lines." The lines are places where a substance breaks easily, and the points are death itself. If a line is cut, then even if the main body survives, that particular part will die, never to move again. If a point is pierced, then the individual will stop functioning completely. Though the eyes are said to see the form of death, strictly speaking, it's more accurate to say they're reading the lifespan of a substance โ the existential limit determined at the moment of creation. The power to take a life is common in the World, however, Shiki's eyes are unique because they directly kill off the meaning/existence of the entity itself rather than their physical body. The extinguishing of life is only a side effect that derives from it. Shiki's eyes ignore the cause of death. Even against that which is immune to all external effects, he kills first. What is killed then becomes "dead". It's not that it stopped because he cut it. In his case, he stops the object, and as a result, it is cut.
The mysteries surrounding the happenings of Misaki Town (Souya), what it means to love life and to covet death, his past and his eyes are all revealed within the story that is Tsukihime. Please enjoy this work to its fullest if you intend to go into it. For that reason, I'll omit spoilers here.