The Black Iron Prison is the Plane of Confinement. Despite it’s name, the prison is not always as apparent as iron bars and stone walls (though it has plenty of that, carved as it was from ancient bones of some demonic titan)--its evil is more subtle than that. Restriction and imprisonment of various forms permeate it.
Portals to the plane are sometimes found on the Material Plane in the form palm-sized, rusted, black iron boxes, heavier than they appear. Visitors to the plane describe an "outer" desert of squalid intern camps, stretched arond and inner, three (or more) dimensional Escher maze of cell-blocks, isolation chambers, and interrogation rooms.
The plane is the home (and the prison) of the deodands, a vile race sentenced to serve as the guards and administrators of the apotheosis prison as punishment for ancient crime. Demonologists have cataloged three primary castes or species of these creatures (though there are undoubtably more):
The middle caste are the color of a fresh bruise. Their limbs are swollen like blood sausages, and their tick-like bellies appear filled to near bursting, sloshing loathesomely as they waddle or fly drunkenly on ridiculously small wings. Their bloated faces are unpleasantly human-like and wear expressions of volutuous satiety, complete with drool running from the corners of their mouths and down their double (or triple) chins. Always their skins appear to glisten as if oiled; this is due to a slime they secrete. They sweat even more when they eat, and they eat almost constantly. They fancy themselves gourmets, and there is nothing they consider so refined as dining on astral substance of souls. They prefer fatted souls, though and first expose victims to their slime. Under the slimes influence, they become grossly corpulent. At that point, they're ready for the slime deodands who drain them to emaciation and let the process begin again. Slime deodands are torturers and interrogators in the deodand hierarchy.
It’s a good thing for Prime Material Plane that deodands seldom arrive on it unbidden. Sadistic sorcerers have been known to arrange “renditions” for enemies, though the price for such a service is rumored to be steep.
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