Gehennom

Gehennom is the hell of nethack. It is found beneath the Valley of the Dead, and is full of mazes. A prayer in Gehennom is considered a prayer to Moloch, which can anger your god, amongst other things. The lairs of several demon lords and princes are found in Gehennom, as are the stairs to Vlad's Tower and the Wizard's Tower, as well a few fake wizard's towers. At the bottom of Gehennom is found the vibrating square. When the invocation ritual is performed on the vibrating square, a downwards staircase to Moloch's Sanctum is created, plus a ring of water and fire traps around you.

Many of the creatures found in Gehennom are resistant to fire, but not to ice, so Frost Brand is a popular weapon for this area.

Gehennom is one of the areas where fire traps can be randomly generated.