ToME WikiI found a town in Nth 666!
Getting There
A purple staircase on the level 148 of the Void leads to the Nether Realm.
Description
The Nether Realm consists wholly of arena levels, with some granite-walled rooms. The floor is a mix of nether mist and lava. The dungeon periodically damages you with nether.
As in the Void, you will forget everything not currently visible to you.
The Nether Realm is the single most difficult dungeon in the entire game, the Void included. Every single monster is leveled to 150! Even normally wimpy monsters such as phantom warriors can do big amounts of damage if they get summoned all around you. Every single trap is leveled more than 40 times! All traps that do damage will average over 1,000 hp.
There are no shafts and using probability travel for quick travel does not work. This means you will have to pass through a minimum of 61 levels on your trip down and back up, but realistically you will see many more levels, since you are likely to end up next to a demon pit more than once and have to retreat. Prepare to spend quite a while of real-world time.
Guardian
The Nether Realm's guardian is Tik'srvzllat. She drops the Flame Imperishable and the Ring of Phasing.