Gehenna Gehenna was an Outer Plane in the Great Wheel cosmology model representing alignments between neutral evil and lawful evil . Description . The four layers of Gehenna were infinite planes with gravity at a forty - five degree angle to the ground , making travelers feel as if they were on the side of a mountain with no base or peak . Anyone losing their footing could tumble for miles / kilometers before finding enough purchase on the slope to halt their fall . Nearly all terrain that was not a river of water or lava was slightly slippery to quite slick . All structures were either built onto or carved into the slopes . Heat and light came from the ground , much like Tarterus , but the source was volcanic : lava flows , vents , fumaroles , and mud pots were very common . Earthquakes and volcanic eruptions occurred often , tearing the land apart . On the hotter layers , unprotected flammable items and creatures would catch fire from the glowing ground or superheated gases being ejected . The barriers between layers were always underground , usually in dead end corridors . Khalas . The uppermost layer , Khalas , was the most livable of the four planes with many waterfalls cascading down the slopes , the largest being the river Styx . The Styx followed a rough path down the slope , fell for thousands of feet / meters , ran through twisty rapids before finally disappearing into underground passages . Steam rose into the infinite and empty black sky making the horizon glow a dull red . Khalas touched the Astral Plane and had connections to Hades , the Nine Hells , and Concordant Opposition . The portals looked like black chasms in the floor of deep underground passages . Markings on the walls would often indicate the portal ' s destination , if you could read them . Chamada . The second layer of Gehenna was the most violently active layer with lava cascades thousands of miles / kilometers wide and city - sized volcanoes yawning open on the slopes . The air was foul with acrid smoke for ten miles ( 16 km ) above the surface and would cause " blindness " to unprotected eyes and had the effect of a " stinking cloud " on the lungs . Below ground the air was fresher but stank of burning flesh and hair . Mungoth . Mungoth was a land of falling ash and burning snow . The furnaces of this layer were fewer and farther apart , allowing ice and snow to build up in the darker places between active areas . Travelers had to brave the never - ending avalanches of wet snow and fiery rock . Underground passages were relatively safe . Krangath . The fourth layer was devoid of any volcanic activity , even underground . All was dark and cold . The name of this layer means literally " dead furnaces " . Inhabitants . The only creatures known to be native to this plane were the barghest s , running through the rifts of Khalas and occasionally found in smaller number on the other layers , and the pyroclastic dragon s . All the other creatures originally came from the adjacent lower planes , mostly to hide from more powerful beings that wished to enslave them . Gehenna was often a plane of exile for the less powerful archdevil s and daemon taskmasters . Realms . Even lesser deities tended to avoid Gehenna . Those that leaned toward Law were recruited into the hierarchy of the Nine Hells and those that favored chaos tended toward Hades . Here is a list of the Powers known to have called this plane home at some point :