Altar

An altar, represented by an underscore, is a place where you may worship gods. An altar with an aligned priest in the same room is a temple.

Altars and priests are co-aligned if they are of the same alignment as you, cross-aligned if they are of a different alignment. An altar is aligned if it has lawful, neutral or chaotic status. Altars of Moloch are unaligned. Unaligned altars do not appear in the main dungeon, only in Gehennom and some quests.

Altars not located in temples are scattered randomly throughout the dungeons. The Valley of the Dead has an unaligned altar located in the temple of Moloch. Minetown is also guaranteed to have a temple altar.

Altars can be used to detect the BUC status of items. This is done by dropping the item onto the altar. A black flash marks a cursed item and an amber flash a blessed one. You can not detect the BUC status if you are blind or hallucinating.

If you #sit on, Engraving, or kick an altar, it will lower your luck. If the altar is of your alignment, it will reduce Wisdom by one point instead.

Sacrificing corpses
You can #offer fresh corpses to your god by sacrificing them on an altar. The greater the monster's difficulty, the more your god will appreciate it. You can gain powerful gifts from sacrifices and may convert opposed altars. Additionally, sacrificing will tell you if your prayer timeout has expired.

The details of the effects of sacrifice follow. Obviously, whatever the outcome of the sacrifice, you lose the atheist conduct. If the corpse is a cockatrice, you suffer the effects of touching it, even if it wasn't in your inventory.

Further effects depend on the details of the sacrifice.

Ordinary sacrifice
This applies to sacrifices made on your own god's altar that are not of your own race, not a pet, not a unicorn, and not made in the endgame.

If the creature is not an acid blob and is greater than 50 turns old (after adjustments for ice), it is rejected: "Nothing happens." (Yes, acid blobs are special: they never expire for sacrifices, although of course they may rot like most food.) Other creatures have a particular value depending generally on their toughness. In some special cases, the value may be negative if the offering displeases your god: see below. Partially-eaten corpses normally get their value decreased by roughly the percentage that's been eaten. zombies can never be sacrificed.

If your god is angry at you, his anger is decreased by 1/8 the value of the sacrifice, if you're non-chaotic; otherwise, by 1/12 the value of the sacrifice (chaotic gods are harder to appease). The decrease in anger is always rounded down. If your god's anger has been reduced to zero, you'll receive the message that he "seems mollified" (if hallucinating, "seems astral (not a new fact)"), and your luck will be increased to zero if negative. If anger is reduced but not to zero, you'll receive the message that your god "seems slightly mollified" ("seems groovy" if hallucinating), and your luck will be increased by one point if negative. If anger has not been reduced at all, "You have a feeling of inadequacy" (if hallucinating, "The gods seem tall").

If your god is not angry at you, but your alignment is negative, your alignment is increased by the value of the sacrifice, up to a maximum of 0 alignment, and "you feel partially absolved".

Otherwise, if your prayer timeout is greater than zero, it's decreased by 12.5 times the sacrifice's value if you're lawful or neutral, or 125/6 (about 20.8) times its value if you're chaotic, obviously to a minimum of zero. If this decreases your prayer timeout to 0, then "you have a feeling of reconciliation" (if hallucinating, "Overall, there is a smell of fried onions"), your luck is increased to zero if negative, and it's safe to pray. If your prayer timeout is not yet zero, "You have a hopeful feeling" (if hallucinating, "You realize the gods are not like you and I"), your luck is increased by one if negative, and it is not yet safe to pray.

If none of the above apply, you generally have a chance of getting an artifact. Your level must be greater than 2, and your luck must be nonnegative. If those conditions are met, the chances of your getting an artifact are 1/(10 + 2&times;number of artifacts that exist&times;number of gifts granted by your god). If you do receive an artifact, you'll get the message "An object appears at your feet!", and your god will tell you to "use my gift wisely!" You exercise your wisdom, your prayer timeout is set to 300 + 50&times;the number of artifacts that exist, and your skill in using the artifact's type of weapon becomes unrestricted.

Whether or not you get the artifact, your luck increases by 5/24 (about 20.8%) the value of the sacrifice, and is set to 0 if still negative. You receive the message "You glimpse a four-leaf clover at your feet" (if hallucinating, "You see crabgrass at your feet. A funny thing in a dungeon"). This luck bonus occurs even if you're below level 3 or have negative luck, but not if you had an angry god, negative alignment, or nonzero prayer timeout.

Sacrificing creatures of own race
If the creature you sacrifice is of your own race, basically, you get good effects if you're chaotic, bad effects otherwise:


 * If you're chaotic, you gain five alignment. If you're a demon, you exercise your wisdom.  If the altar is chaotic, you gain two luck, and if the altar is unaligned, you lose two luck.  Your luck is unaffected if the altar is lawful or neutral.
 * Whatever the altar is, if you're non-chaotic, you abuse your wisdom, you lose 5 alignment, your god's anger increases by three, your wisdom decreases by one point, your luck decreases by 5, and outside of Hell, your god will punish you as for praying too much (depending on the level of anger). Finally, if the altar is chaotic, you'll destroy it and anger any attendant priest.
 * If the altar is lawful or neutral, it will be immediately converted to chaotic (even if you aren't!). This will anger any priests but apparently not suffer the other effects of conversion.
 * If the altar is chaotic or unaligned, a demon will be summoned under some circumstances (need to document these!). The demon will be friendly if you're chaotic and hostile otherwise.

No further effects occur in this case. Oddly, this means that chaotic characters may wish to sacrifice creatures of their own race even at Moloch's altar, if they prefer +5 alignment and -2 luck for some reason. Sacrificing pets of your own race is no different from sacrificing other creatures of your own race in 3.4.3.

Sacrificing pets
Sacrificing pets will generally cause you to lose three alignment and gain the aggravate monster intrinsic. The pet will have a sacrificial value of -1, causing it to worsen certain things that generally benefit from sacrifice. It proceeds as an ordinary sacrifice.

Cross-aligned altars
You can convert cross-aligned altars by sacrificing at them if they're not in Gehennom. If you fail, you will lose 1 luck and possibly have monsters sent in to defend the altar. If you succeed then you gain 2 luck and the altar becomes coaligned. The chances to convert an altar go up with character level.

Danger in sacrificing
Sacrificing can be dangerous in the following circumstances:
 * Sacrificing at an altar of Moloch.
 * You gain 3 anger, lose 5 alignment, lose 2 wisdom, lose 5 luck, and get a negative effect.
 * Sacrificing at an altar not of your alignment type (ie. Lawful, Neutral, Chaotic) when your alignment is negative.
 * This may convert you to the altar's alignment, you lose 3 luck, and your prayer timeout increases by 300. Note that if this happens before you have been admitted to the quest, the game will be unwinnable.
 * Sacrificing at an altar not of your alignment type (ie. Lawful, Neutral, Chaotic) when your alignment is high and you are at least level 7.
 * This will convert the altar but may summon a minion of the altar's original god. The probability varies, but is never greater than 1/4. The probability is higher in NetHack brass and SLASH'EM, see.
 * Additionally, if you do this to convert an altar in a temple with attending priest, the priest will become angry at you.
 * Sacrificing former pets.
 * You lose 3 alignment and gain the aggravate monster intrinsic.
 * Sacrificing your own race if you are not chaotic.
 * You lose 5 alignment and 5 luck, and your god's anger increases by 3. On a chaotic altar, this will summon a hostile demon lord or other major demon. Other altars are converted to chaotic.
 * Sacrificing a unicorn on an altar of its own alignment.
 * Sacrificing a unicorn of your alignment.

Sacrificing unicorns
Sacrificing Unicorns is tricky because the altar's alignment, your alignment, and the unicorn's alignment all factor into the outcome. A unicorn's alignment is represented by its color. The white is lawful, grey neutral, and black chaotic. The points to remember are:
 * Never sacrifice a unicorn on an altar of its own alignment.
 * Never sacrifice a unicorn of your alignment.

Each time you sacrifice a unicorn of a different alignment on your own altar, you get a +5 boost to your alignment and the message "You feel you are thoroughly on the right path."

The rest of the effects are summarized in the following table:

Note:You will lose any god-granted protection whenever your alignment changes.

Prayer timeouts and sacrifice
Sacrificing on an altar reduces your prayer timeout and you get a message indicating the status of your prayer timeout.


 * "You have a hopeful feeling."
 * You may not pray yet because your prayer timeout hasn't expired.


 * "You have a feeling of reconciliation."
 * You may pray because your sacrifice reduced your prayer timeout to zero.


 * "An object appears at your feet!"
 * You may not pray because you received a gift and your prayer timeout has been increased.


 * "You have a feeling of inadequacy."
 * You may not pray. Your god is still angry at you; your sacrifice did nothing to reduce his anger.


 * " seems slightly mollified."
 * You may not pray. Your god's anger has been reduced but it is not yet zero.


 * " seems mollified."
 * You may pray because your god's anger has been reduced to zero.


 * "You feel partially absolved."
 * You may not pray because your alignment was negative, and has been increased by the level of the corpse, to a maximum of zero. Sacrifice again to find if it's safe to pray.


 * "You glimpse a four-leaf clover at your feet."
 * Your luck was increased; you may pray.


 * "You think something brushed your foot."
 * Your luck was increased while blind; you may pray.


 * "You see crabgrass at your feet. A funny thing in a dungeon."
 * Your luck was increased while hallucinating; you may pray.


 * "Your sacrifice is consumed..." and no further message
 * You may pray

Making water holy/unholy
If you drop a potion of water or several potions of water onto an altar and #pray, the potions become blessed if the altar was aligned with you and become cursed if the altar was not aligned with you. This occurs regardless of whether the water was blessed or cursed before. Be aware that praying on a cross-aligned altar will anger your god, decrease your luck, and you might be punished in some other way.

Normal prayer timeouts apply when praying on altars.

Camping/scumming
It is possible to survive indefinitely on a level with an altar. Under normal circumstances, the need for food drives you to deeper unexplored levels. However, you can instead pray when weak, and sacrifice to reduce your prayer timeout back to zero. Doing this for extended periods of time can net you many death drops, and a collection of gifts from your god if your luck is substantially high. This is considered by some as degenerate. It is most effectively done with black puddings, which is known as "pudding farming".

High altars
The three altars on the Astral Plane and the altar in Moloch's Sanctum are considered to be high altars. They act largely as normal altars, but cannot be converted under any circumstances; doing so will cause the god in question to attempt to zap you and, failing this, will summon three minions to protect the altar. In addition, it is not possible to sacrifice monsters unless you are holding them, to stop you sacrificing the riders.

To correctly ascend, one must #offer the real Amulet of Yendor (held in main inventory, NOT dropped on the altar) at the altar of your alignment. Determining the alignment of the altar requires standing on its location and using the : look command. The ; farlook command does not give information about a high altar's alignment. Another method for detecting the correct altar is noticing if you are given sanctuary; that is, all monsters, other than the Riders, aligned priest, and angelic beings, will not be allowed to enter and cannot attack you with melee attacks.

Variants
Players of NetHack brass and SLASH'EM need to be wary when converting altars, because of the increased chance that the altar's original god will dispatch a minion against you. At experience level 7 or above with high alignment, the chance of a minion appearing after converting the altar is the same as vanilla. As in vanilla, the god will yell, "Thou shalt pay for thy indiscretion!" Players with a high luck will have fewer minions dispatched against them.

Even worse, there's an additional chance of one or more minions appearing post-conversion. In SLASH'EM, if you are at experience level 4 or above, there is a chance that "You feel (god) is very angry at you!" and the god dispatches two minions. Afterwards, you still have the original chance of another minion, as above. Again, luck is a factor.

In NetHack brass, you will always receive "You feel (god) is very angry at you!" For all experience levels, at least one minion will appear. Two rolls are made: the first from 0 to 9, the second from 0 to 19. For each roll, if your level is less than the generated random number, a post-conversion minion is summoned. Luck is not a factor. Thus in brass it is very dangerous to convert altars. You might convert an altar at experience level one and have to flee to another level from one minion, or three minions if the game rolled 0 twice, thus giving you no use of the converted altar. If converting an altar at experience level 7 or above, you might still get the pre-conversion minion, forcing you to fight as many as four summoned minions.