Baator
Baator: aka Inferno; the Halls of the Damned; the Fire Below; the Nine Hells. Few names evoke as many dramatic and terrifying images in the minds of mortals as Hell, and rightly so. Baator personifies the epitome of the Lawful Evil ethos as a place of punishment, oppression, and endless, soul-crushing conformity. It is the eternal destination for fascists, tyrants, despots, cruel overseers, malicious judges, unscrupulous barristers, and (most) politicians. Basically, anyone who dominates others through (legal) force or manipulates the law at the expense of others will probably find himself or herself on a one way trip to the big H-E-Double hockey stick when they get their ticket punched.
Baator is made up of nine descending layers that (conceptually, at least) form an inverted cone, with the "largest" layer (Avernus) at the top and the "smallest "(Nessus) at the bottom (although theoretically each layer is infinite in size; go figure). Baator's layers each embody a unique vision of torment, misery, exile, and suffering.
Baator's most notable inhabitants are the baatezu (also known as Devils). The baatezu form the backbone of the infernal hierarchy that runs the Nine Hells. They serve as the rank and file soldiers in its armies as well as the clerks who maintain its labyrinthian bureaucracy. Baatezu are vicious, cruel, and power-hungry schemers who see their subordinates as mere pawns and their superiors as obstacles in their endless grabs for influence and authority. Unlike their chaotic counterparts (the loathed tan'ari), the baatezu frame their actions within a twisted, nearly incomprehensible code of honor.
(more to come)