Penumbra

ripvanwormer's picture

Penumbra is an artificial world created by the ancient Illithid empire.

Penumbra was (and still is, though it has been lost for hundreds of millenia) a disk, with a hole in the center for a full-sized star. Penumbra's
gravity was such that "down" was towards the flat of the disk, making
it effectively two gigantic flat fields, each with more habitable space
than all the planets in a galaxy. (No, really. There's that much
surface area on the darn thing.) The sun perpetually on the horizon, Penumbra was bathed in eternal twilight. Such was the success of this prolific
new species, however, that even a world of that size was not big enough
to supply their needs, and so from Penumbra they launched a campaign that conquered a thousand, a thousand thousand
worlds, spanning endless space and strange dimensions. And chief among
their resources were their human slaves.

Source: Dawn of the Overmind by Bruce Cordell

Planescape, Dungeons & Dragons, their logos, Wizards of the Coast, and the Wizards of the Coast logo are ©2008, Wizards of the Coast, a subsidiary of Hasbro Inc. and used with permission.