Lord Boccob's Tower (DarthCampaign Setting)
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 Lord Boccob's Tower
This is part of the DarthCosmology cosmology
The entire plane is a floating land mass roughly a mile in diameter in the middle of a secluded patch just off the astral plane. The land mass contains an immense tower, as well as several smaller buildings. The weave is visible overhead, though only with an Arcane Sight spell or if one is a deity. The land mass also holds many gardens, trees, and other plant life.
The central tower is where Lord Boccob and most of the other non-evil gods of arcane magic reside. Roughly half of the tower is an immense collection of tomes and scrolls. Of the other half, roughly half of that is arcane laboratories. The remaining 1/4 is living quarters and kitchens and such.
The smaller buildings are mostly the dwellings of other deities of arcane magic who prefer to be outside the tower proper. Most of them resemble oversized ivy-covered huts, except for one. This one is outrageously colored in every hue of the rainbow, with strange angles and decorations outside. This is the dwelling of The Faceless Mage, the demigod of arcane trickery. He is regularly banished from the tower proper for short lengths of time due to pranks, and his hut sits alone on the edge of the land mass.
There are four shimmering portals in each of the four cardinal directions about 1/2 a mile from the land mass proper. These portals can be de-activated individually or all together by Lord Boccob if he so wishes. One leads onto the astral plane (not far from the material plane overlap border), another leads to Common Ground, and the remaining two open near the other two major centers of learning built and inhabited by non-evil deities.
Magic functions as it does on the material plane. So does time's flow. On the land mass gravity is down to the surface, but leaping off of it (even jumping or leaping out a 59th-floor window) will shift your personal gravity to be much like on the astral plane until you choose to have gravity affect you normally, in which case you plummet towards the land mass (as if under a feather fall effect).