The Sithen Citadel
The Sithen Citadel looms large over Dis, the City of Pain, which itself comprises to near exclusion the second of the Nine Hells. Although the city is constructed on an infinite wasteland of smoke and blackened iron, the Citadel can be seen from anywhere within--carving out a malignant gash from every horizon.
The citadel is the final and eternal prison for the souls of false prophets and narcissistic tyrants. Those imprisoned suffer excruciating torment from which there is no escape or reprieve. It is overseen (like the rest of its layer) by Dispater.
Despite the inconceivable size of the structure, the souls condemned to its confines are packed as tightly together as space will allow. Considering, however, that space in Baator is heavily warped--this allowment has few meaningful limits.
Here, the damned are bound about the neck and extremities with chains of an unbreakable, heavy metal alloy. These attach to desks whose tops are invariably jagged and slanted (and which each prisoner shares with as many others as possible).
The chains are infused with various alchemical substances, including a form of sulphite which renders sleep impossible. Found also within these chains are trace amounts of the substance panacaea. Passively, this element ensures that none of the imprisoned can perish into oblivion or to lesser punishments. However, it serves a far more nefarious purpose as well.
The panacaea in the chains becomes an all-consuming addiction for these souls. It is the only thing in their pain-filled existence which even temporarily approaches release from their personal hell. The substance, however, is only released when the soul is actively writing into the Records of Fate which are omnipresent upon their jagged desks.
The final cruelty of the chains arrives with constant, magically-induced visions of every humanoid life on the material plane. The imprisoned souls of the Sithen Citadel spend eternity recording even the most insignificant details of lives that never touched theirs (nor ever will) as though they were all events of dire consequence.
As penance for lying about the divine or the future--or for cruelty toward those they thought inferior to themselves--the damned must dedicate their existence to looking backward in order to record every mundane story but their own.
The Records of Fate compiled here by the condemned are believed, ultimately, to contain a complete record of all humanoid existence on the Prime Material Plane.
The contents are, by their very nature, impossibly disorganized and utterly beyond normal means of consumption. However, it is presumed that--were one able to decode their chaos and cross-reference accurately--one could learn any detail whatsoever about the past or about an individual.
The Citadel was originally designed by Asmodeus himself, whom many believe to be possessed of such an ability.