As with all Supernal Realms, what constitutes Pandemonium has been changed over the years. Mages who know of these changes debate whether this is a result of the Supernal itself changing, or if mortals have developed to the degree that they can see more of the Supernal during their Awakening than before. As access to the Supernal is impossible, the debates are mostly academic.
Around 5000 BCE, Pandemonium was a dark, foreboding forest littered with objects from the past of any mage who entered it. Those who tried to chase these mementos were doomed to walk in circles, while those whose Will could break through the shifting pathways found a singular menhir, the Forest's Heart, in a small clearing. By chipping off a piece of the rock and scarring oneself with it, one Awakened.
Like all the Supernatural Realms, the exact nature of Pandemonium is somewhat subjective. The most common realm experienced by arriving Mastigos is that of a vast network of caverns, without end or outside, populated by a horde of unruly deformed creatures: the demons of Pandemonium. This great maze has no true beginning or end, but winds on and on through throngs of madcap beasts, stretching on into eternity. The pathways and passages are inconstant, shifting from visit to visit; there are some stationary features, although they shift in size, shape and appearance; these are demon kingdoms. Their exact nature shifts, though their theme remains invariable for those who can see them for what they are; the kingdoms of the seven Vices. (Read Dante’s Inferno to get a good idea about these dominions).
Pandemonium is often compared to the idea of the 'shadow' of the collective subconscious, a place of rejected ideas and fallen ideals. Thus, the demons of Pandemonium are identified by scholars from other Paths as dark reflections of creatures native to their Paths; fallen angels, Unseelie Fae, rabid beasts, evil spirits or malevolent dead, dark matter gargoyles; others think the realm is a vision of a possible future: a mass Awakening of humanity without the necessary mental discipline. Each demon is viewed as humans wielding power beyond their understanding and control, their darkest desires and basest urges expressed through their unwise use of magic.
Many mages view the Supernal Realms as stages along the soul's journey to absolute transcendence, vital steps that must be taken before ascension to the place beyond the Fallen and Supernal Realms. If this is the case, then Pandemonium is the place of penitence, where souls are purged of their sins, derangements, cares, obsessions, and attachments to the material world. The moment the soul arrives in this realm, packs of demons descend on him/her, screeching and clamoring with joy as they tear them apart. This torture is not malicious in aspect, though the demons seem to enjoy it; they are a form of spiritual surgery, a way of cutting out the bad parts. There is no anesthetic for this surgery, no peaceful sleep while the fiends do their awful work; the victim has lived too long in ignorance of the pain he has caused others and must now feel its full force. Without this the soul cannot have empathy, nor share in the souls of others, so cannot rise into true until with them.
The Subtle expression of Pandemonium is the Arcanum of the Mind. The Realm of Pandemonium is a place of scourging. The purpose of this place is to cleanse a soul of its sins through punishment, before it moves on to the other Realms. The powers of Pandemonium must reach inside the minds of arrivals to lay bare all their transgressions, worldly attachments and neuroses for systematic purging. The patrons of Massages grant this power to these mages who would wield it in their own name. The Arcanum of Mind bestows mastery over telepathy, mental control, communication, and the nuances of dreams and Astral Space.
The Gross expression of Pandemonium is the Arcanum of Space. The Abode of Demons is a prison for the soul, and although few sentences to its depths are permanent, escape cannot be allowed, lest a soul evade scourging by the wardens and enter whatever lies beyond the Realms Supernal still tainted by vice and materialism. The realm's security system is simple yet extremely effective; escape is literally impossible as its tunnels curve back in on themselves in impossible directions, and any who attempt to flee wind up precisely where they were before. Pandemonium will get its pound of flesh, no matter what, and that's not a euphemism. This power is made available to the wielders of Pandemonic energy via the Arcanum of Space. Those who learn the secrets of the Arcanum can draw on scrying, teleportation, wards, and conjuration.
There are a number of theories amongst the Warlocks as to why their power over Matter is diminished. Some believe that it is due to the lack of metaphysical weight in the Realm to contain or obstruct one's actions. Others think that matter is seen as inimical to demons because it is the only thing that can bind them, and that it’s not present in Pandemonium. Still others theorize that Pandemonium is 'denser' than the other Supernal Realms, and this weight draws it closer to the Material Realm; thus, some of the Material Realm's laws act on Pandemonium. Mastigos cannot easily manipulate matter, as this theory would have it, because the Realm is partially affected by laws of Fallen World matter. Whatever the reason, Mastigos cannot easily wield the Arcanum of Matter.
Inhabitants: The Demons
The principal natives of Pandemonium are, as the realm's name suggests, the Demons. These creatures are the keepers, wardens, and torturers of Pandemonium; they take immense pleasure from their work, stripping down the neuroses of their victims and cutting out the malevolent or corrupted parts. What's more, they're also prisoners, the only permanent prisoners in the entire realm; their anger at this drives them to do their jobs with a vengeance, and indeed, more vindictively.
Many mages see the Demon's role as a form of surgery to remove a cancer, though this tumor exists within the subject's soul rather than the body. Pandemonium means 'The Place of All Demons' in Latin, and this is most certainly of the realm. It swarms with great hordes of Demons in all shapes and sizes, embodying all and every kind of vice, sin and derangement that has ever needed purging from a mortal, and even more besides. These creatures rend and punish the sinful in their Realm, but offer assistance and counsel to Awakening mages (most of the time).
The nature of the Demons is open to debate amongst Pandemonaic scholars. Some Warlocks believe that their Supernal patrons are the exiled or corrupted creatures of other Paths, be they fallen angels, rabid beast, the debased Unseelie or the shade of evil dead. Others say they represent a potential future, a mass Awakening of humanity without the proper discipline and Wisdom to guide them. Each Demon is thus seen as a human wielding unspeakable power without control or restraint, given over wholly to their basest desires and urges. The Demons themselves offer up no solutions to the Awakened, as meaningful contact with them in their own realm after Awakening is a feat that only the arch masters have even a hope of achieving.
The craft of Supernal Summoning identifies two types of being that can be called from a Supernal Realm; manifest beings of the Gross Arcanum of that realm, and recondite beings embodying the Subtle Arcanum.