True Demon [Circumstances]

Even in the world of Extra, the concept of Demons (悪魔の概念, akuma no gainen?) is by humanity treated as the greatest of obstacles; so as God is to omniscience and omnipotence (全知全能, zenchi zenou?), so as demons as an existence are to mortal levels of awareness and impotence (人知無能, Jinchi Munou?, lit. "human intellect and impotence").

They are as an abyss (淵, fuchi?) that lies within arm's reach, yet decisively beyond comprehension.

Distinct from those demons from Stay Night, which exist only as imitations, the real thing -- Enfleshed Demons (受肉した悪魔, juniku-shita akuma?, lit. "Incarnated Demon") are that with which humans are incapable of competing 太刀打ちできない (tachi-uchi-dekinai, lit. "incapable of crossing swords"?).

(※ There is in record only a single instance in which an Enfleshed Demon was forced to disperse (退散, taisan?, lit. "disperse / retreat"), but that's a different story.)

In general, demons are existences that take possession, utilizing the corpus of a human to incarnate (受肉, juniku) and take action, but in the event that the psyche (精神, seishin?) of the human host (苗床になる人間, naedoko ni naru ningen?, lit. "the human that becomes a seed-bed") cannot withstand the strain, it is commonplace for self-annihilation (自壊, jikai?) of the host to occur, dispersing the essence of the demon into the vicinity.

There exist also humans who by way of their own acts (業, gō?, lit. "sins; worldly preoccupations / fixations / absorptions; karma") are subsumed unto the category of Demons as a result of losing their humanity; but these creatures that are said to have become Fiends (魔人, Majin?) cannot be considered True Demons.

In the world of Extra -- whether by way of Demonic possession, or in the circumstance that one's own actions bring about a transformation -- the phenomenon whereby a True Demon is birthed unto the world has, as of present day in 2030, not been brought successful fruition even once.

Though the classifications of "Demons" and "Fiends" do exist, their manner of existence is in essence indistinguishable from that of a higher-order lifeform (高次元生命体, kou-jigen seimeitai?, lit. "higher-dimension lifeform") that inhabits a different sphere of civilization (異なる文明圏, koto-naru bunmei-ken?) upon a different planet (異なる惑星, koto-naru wakusei?).

In sum, said existences can, per the recognition of the Universe of Awareness (認識宇宙, ninshiki-uchuu?, lit. "the universe derived of observation / perception"), no longer be discerned as "human."

Their existences would approximate to that of the cosmic horrors (邪神, jashin?, lit. "evil god") of a certain fictitious Mythos popular in the 20th century.

In the True Route of CCC, a certain individual that has undergone transmigration did indeed manage to reach this realm, but owing to a slight mistake, they were capsized from the Seat of Divinity (神の座, kami no za?-Fate/Extra Mats