Stealth

The Ranger, Thief and Monk classes can effectively become invisible by using their stealth ability, which is also known as the Hide in Shadows ability. This ability differs from invisibility in a few important ways:

the character must pass a stealth check every 20 seconds to see if they've successfully remained hidden;
stealth is more easily broken than invisibility;
it has an unlimited number of uses.

Mechanics[]

The stealth ability is governed by the Hide in Shadows and Move Silently skills. In the original game, these two skills were represented by a single Stealth skill. The starting value of these skills varies based on class, race and dexterity. See the Thieving Abilities article for more information.

In order for the stealth action icon to be enabled, the character must be wearing no armor, light armor (Robe, Leather Armor, Studded Leather) or medium armor (Hide Armor, Elven Chain Mail), though the latter has a stealth penalty. If heavy armor is worn, the stealth button will be disabled. There are a few exceptions to the rule. Both Corthala Family Armor and Mithral Chain Mail do not penalize stealth, acting like light armor despite being Chain Mails.

When a character attempts to enter stealth mode, the first condition checked is whether there are enemies within the character's field of view. Hide in Shadows fails if a hostile creature is within the character’s field of vision. It doesn’t matter whether the character can see them (invisible enemies still count), and it also doesn’t matter whether they can see the character — their mere presence in that vision radius prevents hiding. To illustrate, a few examples:

A Mist Mephit blinds Imoen with a mist ball. Her field of vision shrinks to nothing, so she cannot see the mephit (or any other enemies) and can now attempt to enter stealth—even though the mephit can still see her.
- Conversely, if Imoen blinds the mephit, it makes no difference: she still cannot hide while the creature remains within her field of vision.
A Flaming Fist Enforcer approaches Coran in Chapter Seven to make an arrest. He is not yet hostile. Coran can still attempt to hide, even while under the guard’s gaze.
The dialogue window reports that an Invisible Stalker is attacking Alora. Even though the creature’s location isn’t visible, it’s likely close enough to prevent her from using Stealth. If she can break line of vision by rounding a corner, she may succeed.

The Shadowdancer has an improved version of the stealth ability called Hide in Plain Sight, which allows them to attempt to enter stealth whether they can see enemies or not.

To determine if a character can enter or remain in Stealth, take the average of the character's Move Silently and Hide In Shadows values, and divide this by a number between 1 and 2 based on the current lighting. Then roll 1d100-1. If the die result is less than the calculation, the attempt is successful, and the character enters or remains in Stealth. Otherwise, the attempt fails and the scout leaves Stealth. When stealth is achieved, a text is displayed "Hide in Shadows Succeeded", when the attempt has not succeeded a text reads "Hide in Shadows Failed".

The formula to determine the success of a Hide attempt is:

(((Hide in Shadows + Move Silently) / 2) ÷ Lighting Factor) = Number to roll less than for success on a d100-1 roll

Environmental lighting divider factors range between 1 and 2 - when the character is in darkness, such as outdoors at nighttime, or indoors away from illumination, the lighting divider is 1. When the character is in the open in bright daylight, the lighting divider is 2. When the character is in other situations, such as being outdoors in a shadow during daytime, or indoors but close to illumination, the lighting divider is a fractional number in between 1 and 2, depending on the lighting (the lighting zone map).

The 100-sided die benefits from good Luck and is penalized for bad luck.

Effectively, every 2 points of combined value provides 1% chance of success in darkness, and every 4 points of combined value provides 1% chance of success in bright daylight, both up to 99%. There is no rounding up. For example, a combined value of 15 would provide 7% chance in darkness, and 3% chance is bright daylight.

A die result of 100 always counts as a failure, enforcing a minimum 1% failure chance (unless the character has a good Luck bonus) - good Luck affects the 1d100 roll. A good Luck bonus prevents a die result of 100, negating the enforced 1% failure chance. Bad luck increases the chance of rolling a 100.

After entering Stealth, the character will make another check once per 3 rounds (20 seconds), using the lighting divider that applies at that time. If the check succeeds, the scout remains in Stealth. If the check has not succeeded, two texts will display reading "Hide in Shadows Failed", followed by "Leaving Shadows" - there is a 10 second delay before the stealth effect is finished, and the character can move away or take some other evasive action if desired.

Otherwise, the scout leaves Stealth. There is no benefit to favoring Move Silently over Hide In Shadows or vice versa, except perhaps if planning to use the Potion of Power. Only the combined value matters.

Once the character has entered stealth, the character will effectively be treated by the game engine as invisible. If the character fails to enter stealth there is a one round (6.67 seconds) waiting period before a new attempt can be made. If the character is under a Haste effect, this is reduced to half.

Like normal invisibility, the character can freely move among most enemies without risking detection. Stealth will be broken if actions other than movement are performed, such as if the character:

interacts with the environment (e.g., opening doors/chests, picking something up, attacking, etc.)
uses an action icon, even if no action is ultimately performed. For example:
- swaps weapons via the quick slots (swapping from the inventory screen will not break stealth)
- searches for traps
- selects cast spell menu (even if no spell is chosen)
- selects "use an item" (even if no item is chosen)
travels to a new world area, including districts within a city such as traveling from the Athkatla docks to the slums

Interestingly, characters can often interact with devices without breaking stealth. Also, using a group action icon doesn't break stealth.

If stealth is broken by an aggressive action (such as setting a trap), the character immediately becomes visible. If stealth is broken by other means (such as opening a door or failing the skills check) the character has 10 seconds before they become visible. During this time, characters can avoid detection by breaking line of sight with any nearby enemies. Line of sight can be broken through movement, such as by rounding a corner, closing a door, or simply moving farther away (making increased movement speed a very desirable effect). Detection can also be avoided by using a spell, potion, or magic item to become invisible, but the line of sight must still be broken before stealth can be re-entered.

Note that a character may appear to make a failed backstab attempt that doesn't break stealth. Such attacks are purely cosmetic and occur without an actual attack roll being made. These attacks can be turned off by enabling the No Cosmetic Attacks option on the feedback screen.

When a hidden or invisible character performs a melee attack, they receive a +4 THAC0 bonus. This bonus is unrelated to backstabbing and is therefore awarded regardless of the attacker's class, position relative to the target, or type of melee weapon used. No bonus is awarded for ranged attacks.

Gameplay[]

Since the average of Hide in Shadows and Move Silently is used, there is no benefit to having a higher value in one over the other.
Having both skills at 200 gets the maximum stealth ability even at daytime outdoors. However, there is still a benefit from going over 200 since it offsets the stealth penalty of wearing medium armor.
There is always a 1% chance of failure even with 200 stealth unless negated by luck.
A character's sprite will be shaded when they are standing in shadow.
A blinded character is able to hide anytime, as long as no enemies are present within their extremely narrowed sight. [See Blind Thief Trick.]
Spells and abilities that allow invisible creatures to be seen will also reveal creatures hidden in shadow.
Stealth may or may not prevent a creature from initiating dialog; the behavior varies by situation.

Related items[]

Stealth boosting[]

The following items offer a bonus to either the Hide in Shadows or Move Silently skills.

Armor[]

Boots[]

Cloaks[]

Rings[]

Potions[]

AC boosting[]

The following armors offer improved armor class options for stealthy characters but with a stealth penalty.

Improved versions of the Hide Armor (+1, +2 and +3) were introduced by The Black Pits II: Gladiators of Thay, but are not available to players.