Colloquially known as the Darkness by the ponies of Poneva, and by alicorns, is an aggressive paranormal entity and phenomenon that is reportedly spreading throughout the Inner City, ground zero of the balefire bomb that obliterated the heart of the city. It is first mentioned in Chapter 7 of Fallout: Equestria - Rising Dawn, but makes its first physical appearance in Chapter 11.
The Darkness has been noted, by Poneva locals, to be a terrifying, yet mysterious sight in the Inner City. Its origins are unknown, and what it is doing in the city is equally as obscure. However, the Darkness can refer to one of two things, both fundamentally related, yet different.
The Darkness is a paranormal phenomenon that occurs in the Inner City of Poneva City. It is an amorphous presence that has been seen to manifest and spread (so far, in dream sequences, at least) as droplets of oily black liquid that seep from cracks in the ground and rain up into the sky, and or as a billowing cloud of what is described as 'living darkness' that is capable of spreading and interacting with the environment.
When referring to the actual entity that is the Darkness, the Darkness is an intelligent, seemingly omnipotent magical being that brings with it the aforementioned paranormal phenomenon of the same name, in its wake.
The paranormal phenomenon that is the Darkness can be found lurking in the most hostile regions of Poneva City - the Inner City. While invisible to the naked eye, it is readily observable in dreams, where it can be seen breaking the earth and releasing droplets of gravity defying black rain, as clouds of billowing, living darkness obscure and blacken the skies.
Its ubiquitous, invisible presence has been deduced to be responsible for the proliferation of of ghost sightings in the Inner City, as well as the agitation of the Inner City's hostile denizens, much to the detriment of scavengers, scouts, and all who dare venture into the Inner City. Wherever the Darkness is present, it seems, the density of hostile encounters, physical and paranormal alike, increases.
This paranormal phenomenon is detectable by alicorns. Alicorns that have traveled to the Northern Wastes, and in particular, Poneva city, have noted a disturbing magical interference that is permeating the region - a presence that is stronger in Poneva, and strongest around snow furies.
This disruptive presence is referred to as a darkness that drowns out alicorns' telepathic communication. The darkness is so overwhelmingly disturbing to them, that their connection to Unity is drowned out by what they describe as 'screaming'. It is a 'madness' - a disturbing presence that they attribute to snow furies; this presence intensifies and grows stronger the closer they are to them.
A trio of green alicorns, in search of snow furies, noted that they are difficult to track while in the city. It is much like trying to find a pebble in a sea of sand; in order to dig through the sand, or the darkness, the alicorns must be close enough to see or detect the greater shift in intensity that occurs when they are near snow furies.
It is postulated that the origin of snow furies may be connected to this strange, disturbing presence, and to a greater extent, the dark entity of the same name.
The entity that is the Darkness is characterized by its omnipotent, gravelly, sometimes serpentine voice, often whispering, laughing, or speaking to its victims indirectly as a disembodied voice. Other times, it will attempt to impersonate the voices of its victim's loved one's, using its gilded words to lead them to their deaths or to drive them to despair.
The Darkness has been known to physically manifest as a sinister black shadow with what is described as a curved spike for a horn, using this form to stalk or terrorize its victims. In this form, it appears to hold the potential to physically harm its victims, as it is seen tearing apart concrete as it chased Red Dawn and Candy Cane through the Ministry of Morale hub in Poneva.
In several instances, the Darkness can even impersonate its victims' shadows in an attempt to reassure its victim with false safety, before throwing away its ruse at the last moment to attack.
The Darkness is also capable of manifesting in peoples' nightmares. In the dreams it is known to induce and appear in, the Darkness often chooses to impersonate its victims' loved ones, using these forms to torture and emotionally damage its dream-trapped prey. No matter its chosen appearance, almost always possesses its hallmark, defining physical characteristics upon dropping its ruse: a curved black spike sits atop its head, its eyes are alight in green sclera, and scarlet irises, with rippling waves of violet dark magic exude from its eyes and its gaping, distended mouth.
This mysterious, sinister entity has been known to deliberately rile up and attract Snow Furies, Haunters, and other mutated creatures that inhabit the Inner City. The Darkness has also been observed terrorizing Blast Shadows, swallowing them up in black puddles or engulfing them in black clouds. In the wake of its appearances, blast shadows tend to scatter and flee in terror; those that approach the Darkness scream and writhe in agony, dissipating or running to a safety.
It has been described by ghosts such as Holly that the Darkness can corrupt individuals, dead or alive. Corrupted blast shadows, for example, are extremely unstable, aggressive, and driven mad by the Darkness' influence. They appear and manifest as individuals whose dead forms are drenched in and exuding the same oily black liquid that the Darkness brings with it.
The Darkness is capable of tapping into its victims' minds - dead or alive, and learning a being's memories and fears, using these against them by manifesting as doppelgangers or disembodied voices of their loved ones - again, dead or alive, or implanting and whispering thoughts and subliminal messages in their minds. The most terrifying of its capabilities is its ability to put its victims into dream-like stupors, identifying their worst fears, and manifesting them in nightmares that plague the victim until he or she wakes up. It is presumed that the Darkness does this to toy with living beings, finding amusement in terrorizing ponies in their dreams. However, darker intentions lie beneath this already twisted form of torture.
In Chapter 12, the Darkness attempted to force Red Dawn to confess his love for a nightmarish, zombified Dew Drops by sexually assaulting him. While the reasons of this are, thus far, obscure, it is implied that the Darkness, whatever it truly is, wanted to control Red Dawn, and only by giving it to him willingly can the Darkness do so completely. It did, however, manage to emotionally break him, succeeding in this endeavor when Red Dawn told Dew Drops' nightmarish doppelganger that he hated her, thus breaking free of the Darkness' dream state and returning to reality. If one were not to wake, it can be assumed that one would be terrorized indefinitely until they perish, or give into the Darkness and give it what it wants.
The Darkness has been known to use Dark Magic. Thus far, usage of dark magic has only appeared in nightmare sequences. However, these abilities include the disabling of unicorn magic via the conjuring of black crystals that crystallize over the victim's horn, preventing them from casting any spells. The Darkness has been seen trapping limbs by crystallizing dark magic crystals over its victims limbs, pinning them to surfaces.
It appears that its ability to induce nightmarish, comatose states is derived from dark magic as well.