Concept of Death

The is the innate ability to die, conceptually tied to nearly all existences on Earth. 
== Characteristics ==
Normally, every existence that has a "Beginning" must have an "End" — an "ending time" pre-determined at its point of creation. Such an end is concretized as the Concept of Death that all living things possess: from animals to humans, to the various fantasy beings that originate from age-old myths. At the same time, the Concept of Death is not limited just to that which is conventionally "alive" but applies also to things that, while sentient, have no life in the traditional sense: e.g., the Dead and Spirits without life.
What is more, inanimate structures like walls, locks, and other objects with a "function" also carry the Concept of Death, as do things that have little to no concrete form, e.g.: ESP and Magecraft, such as Bounded Fields, as well as diseases, the very air that organisms breathe, or forces of nature like windstorms and typhoons. Regarding natural phenomena, while it is possible to impose the Concept of Death upon individual events to disperse them, it is impossible to outright "kill" the phenomenon itself (e.g., while one might "end" an individual storm, applying the Concept of Death to the very concept of storms cannot be done).
Kara no Kyoukai 1; Fukan Fuukei - Mystic Eyes of Death Perception.jpg|thumb|Mystic Eyes of Death Perception.
ORT Lostbelt7 Bg8.png|thumb|Beni-enma Alter grants ORT the Concept of Death.
The Concept of Death can be "interacted" with under certain circumstances, such as by bearers of the Mystic Eyes of Death Perception. Said Mystic Eyes, descended from the Authority of the Celtic God Balor, can perceive and bring about the "End" of any existence that bears the Concept of Death. The Concept of Death also can be weaponized. Grand Assassin King Hassan was able to grant Tiamat a Concept of Death, and taught Beni-enma Alter how to do so.
Beings without a Concept of Death are immortal and immune to the Mystic Eyes of Death Perception.
As a completely alien lifeform, One Radiance Thing lacks a Concept of Death and is unable to die by natural means, and must be destroyed physically.
 Tezcatlipoca describes life as something one can die. Even if it's a machine, if it can die it can be considered alive. Regular life, even if every part of its body is replaced with an identical functional copy of itself, will not return to life after having died. Even with advances in medical technology, if a being's heart or brain is destroyed, that being will die. ORT is less like a lifeform and more like a phenomenon, something that refuses to die. Even if it dies, ORT will eventually reactivate as long as its shape remains, and do so automatically with no limit to what can be healed. Each and every one of its cells, from its toes to its nervous system to its brain to its heart, are all considered equally unimportant to ORT as every one of its cell contains every one of its functions.Fate/Grand Order: Cosmos in the Lostbelt - Nahui Mictlan: Golden Sea of Trees Travelogue - Section 19: The Cosmic Tree 
==Characters without a Concept of Death== 
*Arcueid Brunestud (Remake) — Thanks to being a True Ancestor, Arcueid can draw power from the World without limit. Due to this, she is close to being a perfect life form that doesn't even carry a Concept of Death. As her powers derive from the World itself, in order to kill Arcueid, a Conceptual Weapon with the power to kill the World itself is needed.Tsukihime - Near Side: Ciel's Route, 7/Bow in the Sky II - 7th day/October 27 (Wed.)Tsukihime - Near Side: Ciel's Route, 12/Endless Stone - 12th day/November 1 (Mon.) As such a type of weapon doesn't exist, her "death" cannot be caused by external factors.
*ORT (Lostbelt) — Despite being a living organism, ORT lacks a biological "death". Unlike Humans who will not "reactivate" once their bodies "cease to function", machines like ORT can function again if their parts are reassembled and/or artificial organs are installed to substitute the lost ones. Due to this, even if ORT dies once, as long as its shape remains, it will eventually reactivate. ORT can only be stopped if its entire body is destroyed.
*Tiamat
*Ultimate Ones — Each of the Types not only lack the concept of damage, but also the Concept of Death. The only way for them to be harmed and destroyed is for something above common sense to exist on the planet, but the resulting "death" is not necessarily permanent.
==References==
Category:Terminology in Fate/Grand Order
Category:Terminology in Tsukihime
Category:Terminology in Tsukihime Remake
Category:Terminology in Fate/kaleid liner PRISMA☆ILLYA