Stealth

Version 0.30: This article may not be up to date for the latest stable release of Crawl.

This page refers to stealth stat, as well as the general mechanic. For the skill, see Stealth (skill). For the Stealth armour ego, see the list of egos.

The Stealth stat determines how likely you are to be detected. While the Stealth skill may be the most direct way to influence this stat, many other factors contribute as well:

Stealth Score

The measure of a character's stealthiness is its stealth score. A character innately has a base stealth score, which is then modified by various external factors.

Your base stealth score equals:

(3 × Dexterity) + (Stealth skill × 15)

Modifiers

The following modifiers are applied in order:

Confusion

Confusion's penalty applies before all other modifiers.

• Confused: x0.33

Flat Modifiers

Positive

• Armour of stealth: +50 per item
• Artefacts with Slth+: +50 per Slth+
• Mutations:
  • Nightstalker mutation: +50 per rank
  • Camouflage mutation: +50 per rank
  • Thin Skeletal Structure mutation: +50 per rank
  • Translucent Skin mutation: +50 per rank
• Bloodless Vampire: +100
  • Bat Form Vampire: +50
• Merfolk/Octopode in water (even if flying): +50

Negative

• Body armour encumbrance: -2 × (Encumbrance rating)² / 3
• When emitting Silence: -50
• Artefacts with Slth-: -50 per Slth-

Multipliers

Positive

• Umbra: depends on the source; the highest stealth source is used. This only applies when the player is the source of umbra.
  • Ring of Shadows: x1.5
  • Dithmenos: Varies based on piety. Equal to x(piety + 200)/200, or x1 at minimum, x2 at maximum.
• Shadow Form: x2

Negative

• Backlit (Corona, halo, etc.): x0.40
• In shallow water (if not flying, large, or amphibious): x0.5
• Carrying the Orb of Zot: x0.33
• Qazlal: Stealth is multiplied by (200 - piety) / 170 (with a cap of 160 piety). At 6* or higher, this is roughly a x0.24 mutiplier.

The following conditions set stealth to 0:

• Berserk
• Clumsy (Dex=0)
• Sacrifice Stealth

If your Stealth score is below 0, it is treated as though it were 0.

In-Game Display

Although you cannot display your exact Stealth Score, you can get an idea of it in the % screen. Every '+' is 50 stealth, every '*' is 100 stealth, '#' is 150 stealth, and '!' is 200 stealth.

Detection

Every monster has their own Monster Awareness score. Each monster has a base awareness of 10, modified as follows:

Positive Factors

• Monster intelligence: +0 for mindless, +8 for animal intelligence, +12 for human intelligence
• Hit dice: +1 per HD
• If the monster is wandering instead of sleeping: +15
• Any monster that is not natural holiness: +10

Negative Factors

• Monsters under the effects of Ensorcelled Hibernation: -10
• If the player is invisible and the monster can't see invisible: -75

If Monster Awareness is < 0, it is treated as though it were 0.

Each time you move or perform an action, all monsters in your line of sight have a (Awareness + 1) / (Your Stealth) chance of spotting you. How fast or slow this action is does not matter; a Naga and Spriggan with the same Stealth score have the same chance per move to be detected. Once they've spotted you, they'll only lose track of you once you've left their line of sight for a while; this occurs much sooner for mindless enemies than for intelligent ones.

History

• Prior to 0.27, hooves had a minor stealth penalty when not swimming or flying, and Translucent Skin offered less stealth. Also, Felids gained 20 stealth when not swimming/flying, but lost 50 stealth if in Blade Hands when not swimming/flying.