An acquirement is a specific way of generating an item in Crawl that, unlike most item generation, is based in large part on your character's abilities and possessions. The item is biased towards being both good and useful to your character, but there are no guarantees: you may be given an item which allows you to win the game, or you may be given useless junk.
There are only a few sources of acquirements. Most are fairly rare, and those that are more common tend to be not as good. The sources are:
- Reading a scroll of acquirement gives the player an acquirement, with a choice of item type. These are quite rare and valuable.
- When drawn, a genie card has a 50% chance of offering the player an acquirement with a choice of type, exactly as the scroll does. These are extremely rare: the deck of oddities never physically appears, but instead any card drawn has a 1% chance of being a card from said deck. With 7 distinct cards in that deck, that gives any card a roughly 1-in-700 chance of being a Genie card.
- Three deities can give out acquirements:
- Okawaru gives out weapon, armour, and missile acquirements on a fairly regular basis at high piety. His weapons are heavily biased towards having high accuracy and low damage enchantments, and his acquirements are biased toward worse item types than those created by other sources.
- Trog gives out weapons and missiles at high piety, similar to Okawaru. However, his weapons are biased towards having low accuracy and high damage enchantments. Similar to Okawaru, his items are biased towards having slightly worse base types than other sources of acquirements.
- Among all the other junk he throws at you, Xom may occasionally give you acquirements.
- Items in vaults may be created using acquirement code; the most notable example of this would be items in troves. As these items are placed when the level is created, the player obviously cannot choose their type. Not all excellent items found in vaults are necessarily acquirements, though.
Acquirements are affected by a number of different factors. Among those common to all acquirement types are:
- They are biased towards items that match your skills. For instance, a character who has heavily invested in Maces & Flails is fairly likely to receive a weapon in that category should they opt for a weapon acquirement. Similarly, a conjurer who uses mainly Fire Magic will likely find themselves receiving a spellbook with more spells from that school should they choose a spellbook acquirement.
- They are biased against items that you have already seen, the logic there being that if you have seen it, you're probably either using it or have decided it isn't useful. This usually includes items in shops, but those which are far too expensive for your character to buy at present are excluded from being "seen."
- The item is guaranteed to be usable. This means that you will be able to equip it, and using it will not incur penance with your current deity. Note that these guarantees are fairly minimal: acquirement may well give your Armour-based hill orc a robe (although it will be biased against doing so if you have invested in the Armour skill).
- The item will not be cursed, but it may (re)curse itself upon being equipped. There is one exception to this (see below).
- Your race and deity may occasionally also cause changes in the items given. Most notably, Ashenzari worshipers will always receive cursed items. Other examples include food acquirement giving fruit to Fedhas worshipers or potions of blood to vampires.
Note that acquirements are not directly affected by your current depth or location. However, the bias against items you have already seen means that later acquirements do tend to give out rarer items, as the common ones have already been seen. This can often produce better acquirements later on, although how much better depends on the item type asked for, and saving an acquirement for later runs the risk of you dying due to poor equipment before you get the chance.
Specific acquirement types
You receive a branded, randart, or even possibly unrandart melee or ranged weapon that usually belongs to the weapon schools you are skilled in. It helps if you are skilled only with weapons you really want to use in combat.
You receive a good or randart piece of armour or shield, with a small chance of an unrandart. The creation process does consider your skills and even mutations, but the item is not guaranteed to be useful for you. It will, however, be one you are capable of wearing. See armour acquirement for more information.
You receive a random piece of jewellery, sometimes a randart. The game will try to give you something you haven't identified yet but that's not guaranteed. The chance for a randart is flat and doesn't depend on the amount of jewellery you have identified.
You receive a book you don't yet have. Book acquirement doesn't give manuals to spellcasters.
You receive a magical staff or rod based on the following conditions:
- Trog worshipers will always receive rods.
- If a random number between 0 and the total sum of your magical skills is greater than Evocations + 2, you will receive a magical staff. Otherwise, you may receive a rod (80%), or a magical staff (20%).
- If your best magical skill is Fire Magic, Ice Magic, Air Magic, Earth Magic, Poison Magic, Conjurations, Necromancy or Summonings you may receive the matching staff (50%), or a non-enhancer staff (a staff of wizardy, channeling, power, or energy).
- Otherwise you may receive completely random staff (33%) or a non-enhancer staff (i.e. your best skill is Spellcasting, or you already are carrying your best skill's staff).
You receive a random wand, with a greater chance of receiving a wand you haven't identified yet or a powerful wand (e.g. hasting, heal wounds, teleportation, invisibility, etc.).
Worshippers of Fedhas receive fruit. Ghouls receive chunks of flesh. Vampires receive potions of blood. All other characters receive some rations, honeycombs, or royal jelly. Nothing you will really miss unless starving or in dire need to restore your stats.
You receive a large amount of gold, ranging from a few hundred to a few thousand. This can help you pay the entrance fee for a Ziggurat or go on a shopping spree in a bazaar. It can also be helpful for those troves that ask you to give them an overly expensive randart in a shop.