The Abyss

Version 0.13: This article may not be up to date for the latest stable release of Crawl.

The Abyss is a truly bizarre place, ever-changing and twisted. It is filled with all sorts of monsters, mostly of demonic nature, whose common aim is to feast on intruders. It is also the garbage dump for many sorcerers, who delight in sending would-be champions like you to these proving grounds of madness. Reportedly, there is some structure to the chaos, as Lugonu seems to concoct schemes around this place and its denizens. The abyssal rune can be found there. The Abyss can be purposefully reached through portals in the deeper levels of the main dungeon.

A one-way gate to a demon-haunted realm, riven by chaos, its very substance impermanent and whimsical, filled with creatures out of nightmare.

The Abyss is an extra-dimensional chaotic plane without definite shape or form, inhabited by unholy horrors and ruled by Lugonu the Unformed. Whether you end up in this horrible place intentionally or as the result of sheer bad luck, dedicated explorers will eventually find the abyssal rune of Zot and perhaps even a way out!

Structure

The Abyss is an unorthodox five-floor branch, with each "floor" an endless plane of constantly shifting terrain. Travel within or between levels of the Abyss is made difficult by several permanent branch features:

• Abyssal Stairs and branch exits appear rarely and at random. Once you've descended further into the Abyss, it's impossible to travel back to a higher level. There are only descending staircases and portals leading out of the Abyss entirely.
• The terrain constantly changes. Although your immediate surroundings will mostly retain their shape from turn to turn, sections of wall will appear and disappear with every step, and perfectly passable terrain can turn into water or lava even under the player's feet, cutting off and opening escape routes and revealing new monsters. If walls, deep water, or lava should appear in your current spot, you will be shoved in a random direction.
• Mapping the Abyss is impossible. Only tiles recently or currently in your line of sight are shown, and anything that leaves your sight is quickly forgotten.
• The player will be teleported at random intervals. 20% of the time, this teleport will reset the entire map.
• Manual teleports take longer to launch and have a chance to fail. Blinking will always be random, regardless of source, and has a low success rate (11% normally, or 33% for worshipers of Lugonu). The usefulness of teleport control is also severely reduced, only doubling the success rate of your blink attempts.
• You may occasionally see orderly structures in the Abyss. These are often vaults, and may contain powerful monsters, Abyssal stairs, the Abyssal rune, or even a way out. Approach these with caution as they are usually well-guarded.

Entering the Abyss

There are several ways to enter the Abyss; some are voluntary, most are not. Abyssal knights begin the game in Abyss:1, but can leave at will to Dungeon:1 with Lugonu's Depart the Abyss ability or risk searching for an exit. Lugonu worshipers can also travel to the Abyss at any time once they reach piety level *****.

Other players must:

• Enter a portal in Pandemonium, the Labyrinth, or floor 21+ of the Dungeon. The safest method, this will cause you to drop any distortion weapons you're carrying at the gate. They'll be there if/when you return.
• Get banished by a monster spell.
• Unwield a distortion weapon (25% chance).
• Get hit by a distortion weapon (9.9% chance).
• Severely miscast a Translocations or Summonings spell.
• Earn Lugonu's wrath.
• Draw the Damnation card from the deck of escape (may banish enemies instead).
• Step on a Zot trap (3.33% chance).

Exploration and Exit

Exploration of the Abyss is not something to be attempted lightly. The branch is fairly dangerous; while higher level characters can easily survive extended trips here, characters under level 20 or so are usually underpowered to deal with the Abyss' inhabitants for very long, and extremely powerful enemies occasionally generate here. Also, unless your character has 100% mutation resistance, exploration of the Abyss puts you at risk of being malmutated by its inhabitants.

That being said, exploration has its rewards. There is an infinite amount of experience available in the Abyss. Training here is by no means necessary or even suggested to complete the game, and it is much less efficient to train in the Abyss than to do so in Pandemonium or the finite end-game branches, but for high level characters it can also be significantly safer. It is also an excellent place for generating piety for the Shining One and Zin; if you've lost large amounts of piety in the end game, taking a brief detour into the Abyss can help top you off. Finally, although most items found here are fairly common, almost any item in the game can be randomly generated. This is useful when trying to acquire enough common consumable items to pay a treasure trove's entry fee (though conservation is almost a necessity to avoid losing these items as rapidly as you acquire them).

As you wander, you will eventually find Abyssal stairs leading further down. These deeper regions of the Abyss are significantly deadlier than the ones before, cranking up the monster generation rate. The Abyssal rune will eventually appear in A:3 and beyond, always in a vault, with higher odds at the deeper levels, but the greatly increased threat involved leaves players with little incentive to ever go any further than A:3. Lugonu worshipers with at least 5 stars of piety also enjoy a important boost to rune placement chance; they are treated as though they are exploring one floor deeper than normal. Be wary around acolytes of Lugonu, as these rare opponents can send you plummeting further into the Abyss by hitting you with their distortion weapons or casting Banishment on you.

If the rune has not been placed, the game makes a roll each time it places a new item. Any rune on the floor prevents the abyssal rune from being generated. Rune placement probabilities:

• A:3 = 10 in 200 = 5% per item (10% with Lugonu)
• A:4 = 21 in 200 = 10% per item (23% with Lugonu)
• A:5 = 46 in 200 = 23% per item (50% with Lugonu)

Once you have the rune, exits will be discovered at a much faster rate. Branch exit spawning:

• A:1 = 1/7500 revealed tiles
• A:2 = 1/6250
• A:3 = 1/5000
• A:4 = 1/3750
• A:5 = 1/2500
• Holding Abyssal rune: 1/1250

Tips & Tricks

• The enemies found here are only slightly weaker than those found in Hell, so a full complement of resistances (particularly mutation resistance) is recommended. Getting surrounded here can be deadly, but if you can run away for long enough the level will reset, saving you from your pursuers. Swiftness or boots of running are especially useful to speed up exploration, as is Flight to pass over deep water and lava, and Stealth can let you walk away from fights you just don't want to deal with.
• You may be in the Abyss for a long time, and few of its inhabitants leave corpses, so a generous supply of permafood is also highly recommended.
• Getting sent to the Abyss early (usually through Banishment) is often a death sentence, but you may be able to survive long enough to find a gate out. Use every speed advantage you can muster to avoid every combat you can; even if you can defeat some of the weaker foes, you want to spend every possible turn exploring new tiles and generating new chances of escape.
• For weaker players, surviving the Abyss is about mobility and not about XP or treasure. To this end, when you see a monster, you should head in the opposite direction. Levitation and Dig will help manufacture avenues of escape when you're seemingly trapped. Teleport scrolls are for when a horde has accumulated and you're trapped. Since teleports take a while to kick in, consider teleporting on sight when you see speedy, lethal monsters like the Executioner. Blink simply fails too often to be a reliable escape tool. Relatively few monsters can fly: use lava and deep water to strand pursuers. Spawn summons to slow/entangle pursuers. Use quiet dead ends to regenerate HP/MP. Then, get moving.
• When you're actually searching for the rune, consider sticking to Abyss:3 or 4 rather than delving all the way to Abyss:5. It may take a little longer, but the difference in monster spawn rate becomes dramatic once you hit bottom.
• The smartest way to survive the Abyss is to only enter it on your own terms. Read the page on Banishment for tips on avoiding one of Crawl's deadliest spells.

Monsters

• Almost any zombie or skeleton, usually of late-game monsters
• Almost any undead or demon (though tier-1 demons are very rare)
• Rare player species monsters, such as tengu and octopodes
• Humanoid casters, such as wizards and necromancers
• Almost any eyeball
• Any kind of draconian
• Any kind of deep dwarf
• Any uniques you banished to the Abyss
• Several monsters unique to the Abyss:

t Apocalypse crab	X Thrashing horror	X Starcursed mass	X Tentacled starspawn
x Ancient zyme	* Lurking horror	v Spatial maelstrom	* Wretched star

History

Prior to 0.12, the Abyss had only one floor, and finding the rune was simply a matter of wandering it for long enough.

Prior to 0.10, the Abyss' terrain shifting would happen at a much slower pace, and only when you weren't looking directly at it.

In earlier versions, the Abyss would wrap around on itself if you went too far in one direction. Also, banishment to the Abyss was one of the possible results of Hell's mystical force.