Hell is a collection of nine arcane planes, known as the Nine Rings of Hell, bound together in a hierarchical order from least terrible to most. Hell is primarily populated by two types of being: devils and the damned souls of mortals judged evil by Ereshkigal. Each of the nine rings is ruled by an Archdevil, all of whom ultimately answer to Satan.
Hell was one of the first areas of the Arcane Void to be given form and purpose, shaped by Satan--believed by many to be the son of Ereshkigal, fallen from the divine realms--from chaos into law.
The Nine Rings
The first ring of Hell, Limbo, is a dark wasteland. Ruled by Barbatos, it is home to the spectra, souls that have not been fully put to rest. Such beings are often allowed to slip through to other planes as ghosts.
The second ring houses those who endlessly strove for power and popularity, no matter the cost. Ruled by Asmodeus, it is a realm of endless temptation without fulfillment.
Ruled by Beelzebub (also known as Ba'al), the third ring contains the souls of those who could not temper their desires and cravings.
The fourth ring, ruled over by the golden devil Mammon, punishes those who hurt others in their quests for wealth and momentary joys by constantly offering them ways to gain such things through brutal self-destruction.
The fifth ring allows those who have been consumed by rage and hatred to devise their own torments. Abaddon oversees their pain, and enhances it through his three aides the Erinyes.
The sixth ring holds the souls of mortals that sought to destroy the divine--not simply those who rebelled against the gods, but any who fought against the divine spark that exists in anyone truly committed to an ideal or principle. The entire plane exists within Leviathan, the ten-thousand-ton devil.
The seventh ring is for any who inflict violence on the weak, the innocent, and the vulnerable. The brutality and severity of its torture is surpassed only in the lowest ring. It is ruled by Moloch, and home to his children Berith and Soneillon and much of the army under their command.
The eight ring is for those who define themselves by lies and deception, whatever pain it may bring to those around them. Belial, they of a thousand forms, subjects his captives to constant false realities and eternal doubt.
The lowest ring is for oathbreakers, backstabbers, and anyone who violates the trust of those close to them. Lilith, its ruler, and her lieutenant Mephistopheles deal out unfathomable torment to all in her sphere.
At the core of the ninth ring is Satan's home, though he spends much of his time outside of the rings seeking to bring more souls and more power to his realm.
The Four Horsemen also seem to reside in the Ring of Treachery, and respect Lilith's authority while there, though their power and field of influence go far beyond Hell.