Gehennom

Gehennom is the underworld of NetHack, whose entrance is located in the Valley of the Dead. It is situated beneath the Castle, consisting of 20–24 total levels, and is the area that Moloch has hidden the Amulet of Yendor within, as indicated by the introduction text. Gehennom is technically considered its own dungeon branch, with the Valley as its first floor, but begins where the main dungeon terminates.

Levels

Gehennom is full of mazes. Among these are the lairs of several demon lords and princes (including Orcus Town), an upstairs branching off to Vlad's Tower, the Wizard's Tower, and a couple of Fake Wizard's Towers (one of which contains the portal to the main tower).

The second level of Gehennom from the bottom contains the vibrating square. When the player performs the invocation ritual on the vibrating square, it creates a down staircase that grants access to Moloch's Sanctum - the lowest level of Gehennom and the dungeon as a whole. While performing the ritual is the only way to gain access to the Sanctum, it can be entered like any other level afterward (e.g., via level teleport).

The following special levels will always occur within Gehennom in each game, with their level ranges given as follows:

• Valley of the Dead (1st level of Gehennom, Dungeon Level 26–30)
• Asmodeus' Lair (2nd to 7th level of Gehennom, DL 27 to DL 36)
• Juiblex's swamp (4th to 7th level of Gehennom, DL 29 to DL 36)
• Baalzebub's Lair (6th to 9th level of Gehennom, DL 31 to DL 38)
• Orcus-town (10th to 15th level of Gehennom, DL 35 to DL 44)
• Wizard's Tower (three consecutive levels, 11th to 18th levels of Gehennom, DL 36 to DL 47)
• Fake Wizard's Towers (two separate levels, 3rd to 6th levels from bottom, DL 40 to DL 51)
• Vibrating Square (2nd level from bottom, DL 44 to DL 52)
• Moloch's Sanctum (Bottom level, DL 45 to DL 53)

Additionally, there will be a set of stairs leading up to Vlad's Tower somewhere between levels 9 and 13 of Gehennom (DL 34 to 42). This up stairway can be on any of the special levels which may occur between levels 9 and 13, but the Tower itself is not counted as part of Gehennom - this is signified when you enter and are informed that "the heat and smoke are gone".

All levels of Gehennom that are not special levels (in the above list) are ordinary maze levels. See Mazes of Menace for a schematic illustration of the possibilities.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that the information below is still accurate, then update the page to incorporate it.

Gehennom's non-special levels now consist of a mixture of mazes with walls of water and icy floors and open cavern-like levels somewhat similar to the Gnomish Mines that are surrounded by lava - the special levels may also have rivers of lava flowing through them as well, save for Juiblex's lair.

As of commit 6acf5a77 and commit 4a00b66b, the ground on Gehennom levels is hot, and may boil non-oil potions that are dropped. The floors on icy levels may similarly freeze dropped potions.

Monsters

Gehennom is coded to exclude lawful monsters; note that this does not include special rooms such as graveyards and zoos, nor special levels within the branch that contain monsters of a specific monster class.

The following monsters are specifically excluded from normal monster creation in Gehennom, and are defined by the tag G_NOHELL in monst.c:

• freezing spheres
• frost giants
• ice trolls
• ice vortices
• winter wolves and winter wolf cubs

Conversely, these monsters are only subject to normal random generation in Gehennom, and are defined by G_HELL in monst.c:

• all & major demons other than foocubi
• disenchanters
• fire vortices
• green slimes
• hell hounds and hell hound pups
• lemures
• master and arch-liches
• salamanders
• steam vortices

Religion

Moloch is the only god with any power in Gehennom - any religious activity requiring interaction with your deity is considered to be directed to Moloch. As such, prayer in Gehennom will only result in negative outcomes - a consequence of this is that if your two-handed weapon is cursed while in Gehennom, you can't count on prayer to uncurse it. Your god still takes note of your actions in Gehennom so, e.g., killing a pet can still decrease alignment record and increase divine anger.

Sacrificing at the altar in the Valley of the Dead, Orcus-town, or Moloch's sanctum will anger your god and reduce your alignment record, wisdom, and Luck - oddly, same-race sacrifice on altars in Gehennom works much as normal for chaotic characters, though the altar will remain unaligned and they will still lose Luck.

This also means that Elbereth has no effect, and attempting to use the turn undead command will fail (although the spell still works).

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that the information below is still accurate, then update the page to incorporate it.

Per commit 18a77b1c, altars to Moloch can be randomly generated in Gehennom.

Strategy

Obtaining fire resistance before entering Gehennom is recommended - while not the difference between life and instant death as with its predecessor of Hell, it is still vital to prevent Gehennom's fire traps from reducing your maximum HP when triggered. Fire resistance will not protect your inventory, so be sure to fireproof your equipment and bag any potions and scrolls that you might want to keep. Magic resistance is also near-essential, as there are many powerful spellcasters within - in particular, master and arch-liches are covetous and can warp to you an cast a spell before you can react.

Many of the demons and other monsters found in Gehennom are resistant to fire but not to ice - Frost Brand is a popular weapon for this area, as is Demonbane to a lesser extent. Silver sabers are also effective against demons, shades and vampires, with the artifact saber Grayswandir being the most effective for Gehennom by far.

Holy water works as normal, but fire traps make them and the scroll of remove curse risky to carry in open inventory. Furthermore, if your weapon and shield (or two-handed weapon) become cursed, you will not be able to retrieve bagged potions and scrolls reliably or pray to uncurse them. In addition to taking the above risk, you can use the #tip extended command to empty a container and get at your curse-removing items.

Maze levels are tedious and time-consuming to explore manually, and this has given Gehennom a reputation as a boring phase of the game. See Gehennom mapping for suggested mapping strategies.

History

Gehennom is introduced in NetHack 3.1.0 - in previous versions, the underworld was called Hell, and required fire resistance to enter and traverse the area without immediately being burnt to death.

Origin

Gehennom is a name for the Valley of Hinnom (or Gehinnom) that surrounded western parts of Jerusalem's Old City; the name is derived from the Aramaic Gehenna. Gehennom plays a significant role in the Hebrew Bible—several chambers for burial and cremation were located in the valley, and some of the kings of Judah were said to engage in Moloch-worship there (hence Moloch's association with Gehennom in NetHack).

The book of Jeremiah has the practice forcibly ended with the destruction of the valley's shrine, and Jeremiah prophesies that Jerusalem would meet a similar fate. Combined with the aforementioned practices, this made the area and its name synonymous with an image of destruction, where wicked souls were sent to be purified (i.e., the Valley of the Dead). While distinct from other abodes of the dead within biblical and rabbinic literature, the King James translation refers to it as "hell", influencing its portrayal in art, literature and other media.

Variants

Many variants are based on NetHack 3.4.3, which did not yet have the #tip command. For those variants and earlier versions of NetHack, it is common to leave a cache of holy water potions or scrolls of remove curse in certain locations to access in the event cursed items leave you without a free hand.

Lethe patch

The Lethe patch includes a restructured Gehennom, including a number of unique levels.

SLASH'EM

In SLASH'EM, Gehennom consists of only 17 levels, but includes lairs for all of the unique demons:

• 1st level: Valley of the Dead
• 2nd through 6th levels: Four of these five levels are demon lairs, one each for Juiblex, Yeenoghu, Orcus, Demogorgon.
• 7th through 9th levels: Wizard's Tower
• 10th through 15th levels: Four of these six levels are devil lairs, one each for Baalzebub, Geryon, Dispater, Asmodeus. The other two levels contain Fake Wizard's Towers.
• 16th level: vibrating square
• 17th level: Moloch's Sanctum

Of note is that Demogorgon's lair is infamously always above and before Asmodeus's lair, with Demogorgon being the most dangerous opponent by far while Asmodeus is typically the easiest.

The up staircases to Vlad's Tower and to Frankenstein's Lab are somewhere amidst the 3rd to 12th levels.

UnNetHack

UnNetHack implements several changes to reduce the tedium of the mazes in Gehennom, mostly from the Heck² patch and portions of the Lethe patch. Certain special levels have been modified or given alternate versions, including the Valley of the Dead, Moloch's Sanctum, and the lairs of the various demon lords. Two new branches can be accessed through stairs throughout Gehennom, (and possibly also through portals in the Valley of the Dead): the Dragon Caves, and Sheol. Additionally, several new monsters appear in Gehennom and Sheol.

FIQHack

In FIQHack, wearing the Mitre of Holiness allows you to pray in Gehennom (including using #turn).

There are additional rooms in Gehennom, including some special rooms backported from xNetHack.

The Fake Wizard's Towers can still spawn as regular rooms, but will never have a portal - the real Wizard's Tower can be entered from the bottom floor.

xNetHack

In xNetHack, Gehennom is significantly revamped and restructured as of version 8.0 - each archfiend is given their own floor in a manner that is distinct from other variants which do the same.

External links

• NetHack Gazetteer: Gehennom describes the layout of Gehennom in vanilla NetHack.