This temple lies underground. The Empire, seeing the use of its very large chambers, has recently had a clockwork factory built on top of it. The Empire cleared the place of all its inhabitants and furnishings, and re-purposed the massive chambers to be launch silos for their Clockwork Dragons.
Main Rooms (green)
The temple itself consists of a large circular hallway that connects 5 very large circular rooms, each room having had a purpose for Zon-Kuthon's worshipers, until The Empire came in and took over. The Empire attempted to take over the entire temple, but they were unable to get past the door leading into Zon-Kuthon's chamber, and after several people died by taking from the treasure room sealed off the inner rooms.
Treasure Room (blue)
This room is populated by whatever possessions those who enter want most. These items will appear to function as intended by all who entered the room, but to all others will not, and will explode upon one of two conditions: either the person removes the sword in the next room, or leaves the temple grounds. In addition there is the Book of Incantations set atop a pedestal here.
This room serves as a barrier to enter Zon-Kuthon's Chamber. Here, only visible by the most powerful of magic, is a seemingly empty room, that has an angel pinned to the floor on a runic symbol. The sword and symbol keep locked the door to Zon-Kuthon's chamber, and also make it so that the door can not be bypassed in any way. One cannot interact with the angel and sword unless they know they are there.
A room full of pits obscured by magical darkness, and dark crystals. On top of a throne of skulls, with enslaved angels at his feet, sits Zon-Kuthon.