- It is a plane without charity, mercy, or pity.
- It is the Oven of Perdition, the Fourfold Furnaces.
- It is where yugoloths cavort on endless volcanic slopes.
Gehenna's top layer borders Hades and the Nine Hells, so it is not a pleasant place. Floating in an impenetrable, infinite void are volcanic mountains seemingly without base or peak. They are only finite in the strictest sense of the word, measuring hundreds of thousands of miles in each direction. A single volcanic mountain dominates each of the four layers of Gehenna, though lesser volcanic earthbergs drift and sometimes smash into the greater mountains.
There is no naturally occurring level place in any of the layers; all the slopes are at least 45 degrees, and many are akin to sheer cliffs. Gehenna's fiendish inhabitants have carved artificial ledges, some large enough for entire cities, and switchback paths to connect them. But those edifices not carved by native yugoloths or deities have a tendency to break apart, sending their builders on a long, sliding fall down the mountain. Gehenna's four layers are Khalas, Chamada, Mungoth, and Krangath. Each layer is differentiated from the other by its degree of volcanic activity. Powerful entities that possess realms on Gehenna include many lords of the yugoloths, as well as Melif the Lich-Lord and Memnor, deity of evil cloud giants. The realm of Maanzicorian, an illithid deity, was once located here. But Maanzicorian was slain by Tenebrous, the name taken by the demon lord Orcus when he first returned from supposed annihilation. Accordingly, Maanzicorian's realm has started to crumble, its deity gone.
- Normal Gravity: Gravity is similar to the Material Plane, but naturally occurring volcanic mountains seem to float free in an infinitely larger void. Gravity is normal on the steep slopes of a mountain, and a fall tumbles victims many miles until a chance ledge catches them, or continued rolling abrasions of the fall completely shred the victim.
- Normal Time.
- Infinite Size: The impenetrable void of Gehenna is infinite, but each volcanic mountain is finite. Each is far larger than the largest known land mass on the Material Plane, however.
- Divinely Morphic: Memnor and other deities can alter Gehenna's mountainous landscape. Ordinary creatures find Gehenna is as alterable as the Material Plane.
- No Elemental or Energy Traits.
- Mildly Evil-Aligned: Good characters on Gehenna suffer a –2 penalty on all Charisma-based checks.
- Normal Magic.
Like all the lower planes, Gehenna has the River Styx flowing through at least its first layer, Khalas. In fact, it is the biggest river on the layer, and it hurtles through gorges and canyons with breathtaking speed. Its cataracts are legendary, and the occasional ledge creates waterfalls of epic, if polluted, proportion. Attempting to change planes via the Styx is a very dangerous thing indeed, on Gehenna. Portals to other planes are fairly common, as are portals between layers of Gehenna. They usually appear as bottomless black chasms. Sometimes they are marked as portals, but sometimes yugoloths mark actual bottomless chasms as portals by mistake or with malice.
The yugoloths, masters of schemes, are most at home on Gehenna, though sages note that yugoloths actually originate in Hades. But the yugoloths have been on Gehenna longer than most of the deities who now have their realms there.
Petitioners of Gehenna are the refuse of the planes. Greedy and grasping, they care only for themselves. Expect no favors from such a petitioner unless proof of immediate recompense is at hand. Unlike on many of the other Outer Planes, petitioners on Gehenna are more willful, traveling from layer to layer on their own personal quests for power. They're looking for the ultimate exercise in free will, though they are destined to never find it. Gehenna's petitioners have the following special petitioner qualities:
- Additional Immunities: Poison, acid.
- Resistances: Fire 20, cold 20.
- Other Special Qualities: Surefooted. Surefooted (Ex): All petitioners have a +10 competence bonus on Climb checks.
Movement and Combat
Movement on Gehenna is much like movement on the Material Plane, though the mountainous, sloping nature of Gehenna imposes constant dangers.
Falling on Gehenna Because every natural surface on Gehenna slopes at least 45 degrees (except for occasional ledges and artificial constructions), moving from place to place is dangerous. The description of the Climb skill in Chapter 4 of the Player's Handbook describes how characters move about on Gehenna's slopes. The DC for Climb checks on Gehenna varies from 0 for ordinary slopes to 15 for steep areas and 25 for sheer cliffs. Creatures can move at one-quarter speed as a moveequivalent action on the sloping surfaces, or at one-half speed as a full-round action. Attempting to move faster incurs a –5 penalty on the climb check, as described in the Player's Handbook. Those who fail their Climb checks make no progress. If they fail their Climb checks by 5 or more, they fall. If a fall occurs, the victim rolls, bounces, and rebounds off the endless steep slope of Gehenna. Falling characters get a chance to catch themselves by making a Climb check (DC 10 on a slope, 35 in a steep area, and 45 on a cliff). If the fall occurs in a random location, the victim comes to a stop on a natural ledge some 10d10+100 feel farther below and takes 10d6 points of damage from the bouncing, bone-jarring descent. In some locations on Gehenna, a victim's fall could end sooner—in a river of lava.
Combat on Gehenna is much like it is between two climbing foes on the Material Plane. Anyone on the surface of Gehenna's mountains loses his Dexterity bonus to AC and cannot use a shield. Attackers get a +2 bonus to attack climbers, even if they're climbing themselves. A climber who takes damage must immediately make a new Climb check against the DC of the slope. If the climber fails, he immediately falls, taking damage as described in Falling on Gehenna, above.
Each layer of Gehenna (called a mount) is slightly different, but each burns with an evil will. The lava flows seem to seek out the casual traveler, and fissures open under a visitor's feet as if the ground itself hungers. As on Carceri, the sloping earth itself provides light, so shadows stretch upward.