Vulnerability

Not to be confused with the scroll of vulnerability, which has a different but related effect.

Vulnerability is a specific weakness in the protections or defences surrounding someone or something. In Crawl, monsters and players can be vulnerable to any of a number of elements, to varying degrees.

Players

Players can be vulnerable to fire, cold, poison, holy, or silver effects. In most cases, being vulnerable to an element causes that element to do 150% damage to the player. Poison vulnerability also causes poison to last twice as long as it ordinarily would. Silver behaves differently than the others; the additional damage it causes scales with the number of mutations you currently have instead of being determined by specific ranks of vulnerability.

Note that for fire and cold resistance, there is no difference between having one level of vulnerability and having three, other than needing more resistance items to compensate for the vulnerability.

Also, note that holy vulnerability does not specifically relate to weapons of holy wrath. Those weapons deal extra damage to demons and undead; holy vulnerability itself usually only concerns cleansing flame and similar effects, which are rare to find targeted against players.

Sources of player vulnerability are, by element:

• Cold
  • Rings of fire give one level per ring worn.
  • Having the spell Ring of Flames active.
  • Being in Dragon Form gives one rank of cold vulnerability (except for non-red Draconians).
  • Artefacts can occasionally have the property.
• Fire
  • Rings of ice give one level per ring worn.
  • White Draconians that cast Dragon Form gain one rank of fire vulnerability
  • Being a mummy.
  • Occasionally found on artefacts.
• Poison
  • Players can only acquire poison vulnerability through the spell Spider Form. Having poison resistance from another source can negate the vulnerability, but having two sources will not make you resistant.
• Holy
  • Being undead, whether naturally or through the spell Necromutation. The undead races can never be rid of this vulnerability, although thankfully, holy attacks are fairly rare.
  • Worshiping an evil god: Beogh, Lugonu, Kikubaaqudgha, Makhleb, or Yredelemnul. Notably, Trog is not considered evil.
• Silver
  • Each mutation you possess increases damage from silver weapons by 5%.

Monsters

Monsters can be vulnerable to the same elements as players, namely fire, cold, and poison. Vulnerability works fairly similarly, except that it is only ever one level for monsters, and it causes them to take 200% damage from elemental melee damage instead of 150%. They can gain vulnerability through items just as players do, and many monsters start off with elemental vulnerabilities.

As stated above, holy vulnerability does not specifically relate to weapons of holy wrath. Holy weapons only cause extra damage to monsters which are demonic or undead; many "evil" spellcasters also have holy vulnerability, but do not take extra damage from weapons of holy wrath. They will, however, take more damage from player-invoked cleansing flame.

A non-exhaustive list of monsters vulnerable to the various elements is given below:

• Cold: Many "fiery" monsters are vulnerable to cold. This includes but is not limited to:
  • Brimstone fiends
  • Balrugs
  • Dragons
  • Crimson imps
  • Hellions
  • Fire elementals
• Fire: Many "icy" monsters are vulnerable to fire, along with a few others. Some examples are:
  • Ice fiends
  • Blizzard demons
  • Simulacra
  • Azure jellies
  • Mummies - but note that the more dangerous types of mummies found in Tomb are not vulnerable to fire.
  • Another notable exception to what one might expect: Despite their description as dessicated corpses, liches are not vulnerable to fire, although they do not resist it either.
• Poison: In general, poison-vulnerable monsters are insects, who absorb air through their skin instead of breathing it, making them more vulnerable to poison.
  • Worker ants
  • Scorpions - but note that emperor scorpions are not vulnerable; in fact, they are poison-resistant.
  • Killer bees
  • Fire crabs
  • Spiny worms
  • Spriggan riders - vulnerable since their giant firefly mounts are vulnerable.
• Holy: This includes everything that could vaguely be classified as a demon or undead, as well as many "evil" creatures. Examples include:
  • All monsters with the "demonic" flag: in console, demons are quite easily distinguished by their numeric glyphs. All the typical denizens of Hell and Pandemonium fall under this category.
  • All undead monsters. These include liches, mummies of all types, skeletal warriors, and all skeletons, simulacra, and zombies. Note that profane servitors are resistant to cleansing flame.
  • Abominations.
  • Many "evil" uniques: Jessica, Josephine, Saint Roka, Frances, Nergalle, and a few others.
  • Monsters that cast powerful necromantic spells, such as deep elf death mages, deep dwarf necromancers, and orc sorcerers.
  • Monsters in the service of evil gods, including orc priests, deep elf priests, and deep dwarf death knights.