It is known that an angel is a divine being charged with a particular task. Indeed, the ultimate etymology of “angel,”—though English acquired the word via Latin and Greek before—is Semitic, cognate with the Post-Biblical Hebrew “igeret,” which has the meaning of something like a “letter.” That is to say, an angel is a being which comes “bearing a letter”: it comes to perform a specific deed and, furthermore, it vanishes the moment it has accomplished it. There are, of course, a number of more “permanent” angels, whose tasks are ongoing and inexhaustible, such as Satan and its task of drawing humans toward wicked acts, in rebellion against their Creator. But these are really exceptions which prove the rule, which can be found in innumerable places in the various scriptures.
What is less widely known as the above is that these angels, which are more like “tendrils” of the Divine than they are independent agents—as we know that, unlike humans and demons, they lack free will—they do not truly “vanish.” A more accurate description would be that they are “severed” and become “sterile.” They are “severed” in the sense that, were they still “directly connected” to the Divine, they could never truly cease to exist, as existence is the primary attribute of God. And they are “sterile” in that they no longer possess any way of interacting with reality at any level, above or below the human realm.
An infinite number of angels are dispatched anew at every moment, sent on any and every conceivable mission, from collapsing the wavefunction of a wayward positron falling into red dwarf, to inciting a Malaysian man to run amok—and, to borrow a mathematical term, “almost all” of them become Sterile Angels. Almost all of these once-eternal, supernal beings become ghastly nothings, unaware even of each other, wandering stochastically through, above, below, and beyond all spaces and times. They are never returned to their Maker, curiously enough, as one might imagine.
Despite their ontological sterility, there are, of course, chance meetings between these dead angels and human beings, the etiology of which is unknown. (Without such meetings, their existence, such as it is, would of course not be known.) Often mistaken for ghosts, their identity is revealed by their incessant babbling. Beginning as a kind of manic glossolalia, the sound eventually shifts into the native language of the listener as the Sterile Angel begins to realize that it is being “seen” by a human being, though this is invariably to the latter’s great misfortune. The chattering of these awful, fallen wights is always more or less the same: “Where am I? What am I? What is ‘where?’ What is ‘what?’ What is ‘what is “what?”’ Where is ‘what’? Who are you? What is ‘who?’ Who is ‘what’? What is ‘what is “what is ‘what?’”’”
This continues at a more and more frantic pace and clearly horrified timbre, always ending in an almost continuous buzz, consisting of, “What am I?” and “Who are you?” repeated until the Sterile Angel lapses back behind the screen obscuring all other broken and terrible things from the incautious eyes of sane creatures.