Gehennom (EvilHack)

In EvilHack, Gehennom has been significantly revamped from its layout and composition in vanilla NetHack. The depths of Gehennom are filled with hellish-caverns and rivers of lava, and fire resistance is required to avoid being burned alive: a hero that does not have full fire resistance will take fire damage each turn ("The flames of hell are <slowly> roasting you alive!"), with the damage proportionate to the amount of fire resistance the hero has.

Gehennom guarantees that heroes will encounter four different demon lords and princes within more elaborate lairs, and the demon rulers themselves are more deadly than in most variants—while the demon and devil rulers are not invincible, the average hero will require far more strategy and higher-quality equipment in order to reliably best them and advance to The Wizard's Tower.

Generation

As in NetHack, Gehennom is situated beneath the Castle and consists of 16 to 20 levels, with the Valley of the Dead as its first floor.

Levels

The levels that compose Gehennom are described below.

Valley of the Dead

The Valley of the Dead's map is changed somewhat from NetHack, and includes the previously-deferred Cerberus and Charon. The stair to Gehennom cannot be accessed until Cerberus is killed, nor can a hero level teleport or successfully use a cursed potion of gain level to leave the level until he is dealt with.

The Hidden Dungeon is accessible through a magic portal found in a specific area of the Valley—within the branch lurks Tal'Gath, a very powerful beholder that must be killed in order to be able to genocide other beholders.

The hero's normal HP regeneration is suppressed while in the Valley of the Dead unless they are undead, a draugr or a vampire, though other methods of healing are not impacted.

Filler levels

Gehennom's filler levels are Gnomish Mines-style caverns levels filled with lava, and some of these levels will contain stairs or magic portals to other dungeon branches:

• The magic portal to Vecna's Domain can be found on the first level below the Valley of the Dead.
• The stair to Vlad's Tower can be found anywhere from levels 34 to 42.

Demon lairs

The demon rulers and their lairs are randomized each game: there are three tiers of lair that become progressively more difficult, and each of them have their own set of maps and randomly-chosen rulers—the first two tiers host demon lords, while the third hosts a demon prince. The demon prince Orcus is not counted among these, as he is guaranteed to appear and is found in Orcus Town. In the presence of a demon ruler, the odds of escaping by teleportation, level teleportation or quaffing a cursed potion of gain level are lowered to ¹⁄₅ for demon lords and ¹⁄₂₀ for demon princes—additionally, if the hero attempts to level teleport past a demon ruler's lair, that demon will follow them, awakening from any meditating state if necessary.

The following tiers of demon ruler can be encountered:

• First tier: Juiblex, Baalzebub, Geryon, or Baphomet
• Second tier: Dispater, Yeenoghu, Lolth, or Mephistopheles
• Third tier: Asmodeus, Demogorgon, Tiamat, or Graz'zt

Vlad's Tower

Vlad's Tower is heavily revamped from its appearance in NetHack, and features far more dangerous vampires alongside an entrance that is blocked off by a deadly abyss.

The Wizard's Tower

The Wizard's Tower is also heavily revamped and made into a fully separate branch from Gehennom in comparison to NetHack. There are still "Fake Wizard's Tower"-like structures within Gehennom, which have a much different appearance, and one of them hosts the two-way magic portal leading into the Wizard's Tower.

The vibrating square

The level containing the vibrating square is still a maze level as in NetHack.

The Sanctum

Moloch's Sanctum has also been overhauled significantly from its appearance in NetHack. Here, the Amulet of Yendor can be found in the possession of the high priest of Moloch—once the Amulet is obtained, however, the up stair is blocked off, and another part of the Sanctum appears that must be traversed, with the demon prince Lucifer guarding the path to Purgatory.