Stealth

Stealth is the combination of Hide and Move Silently. It is opposed by a target's Perception.

Check
In order to enter Stealth, you must have cover or concealment relative to your potential observers, and you cannot be under active observation, even casual. Entering Stealth takes no action, and is done as part of a movement. While in Stealth, you remain unnoticed unless your observers succeed on an opposed Perception check.

You remain in Stealth until you choose to make yourself known to your observers, or until you take an action that would cause your observers to notice you. Such actions include attacking, or moving in such a way that you no longer have cover or concealment relative to your observers.


 * Example: You have entered Stealth behind a crate in an alleyway as your target passes by you. As long as the crate remains between you and your target, you remain in Stealth, and as long as he doesn't beat your Stealth check with his Perception check, he doesn't notice you. If you attack him, or move out from behind the crate to approach him before his back is turned, you automatically leave Stealth.

A certain amount of DM adjudication is unfortunately necessary to determine whether or not a target would be facing you. In general, a stationary target is "facing" the square directly in front of him, as well as the two squares on his front diagonal and the two squares to his side, while a moving target is facing the square along his path of motion and the two squares on his front diagonal. However, some creatures may have a wider or narrower field of view.

Approaching a target in his facing squares automatically breaks Stealth. Approaching a target on one of his non-facing squares gives him a second Perception check to notice you. Attacking automatically breaks Stealth, but see "Sniping," below.

If one creature notices you, he may point you out to all of his allies as a free action during his following turn. Doing so automatically breaks your Stealth to all of those allies.

Once you have been noticed, you may not re-enter Stealth until you gain total cover or total concealment from your observers (such as by ducking behind a corner or diving into some bushes). Even in those situations, your observers will be able to see you until you enter full cover.

You can move at up to one-half your normal speed at no penalty while in Stealth. Moving up to your full speed incurs a -5 penalty; moving faster than this, including taking the Run action or charging, incurs a -20 penalty.

Total cover or total concealment generally obviates the need for a Stealth check, as your targets would be unable to see you anyway. If you are invisible, you gain a +40 to your Stealth checks if you are invisible, or a +20 if you are moving.

Sniping: If you are 10 feet or more from your target and in Stealth, you can make a single ranged attack and then immediately re-enter Stealth. You can move, or not, at your discretion. You take a -20 penalty on your Stealth check when doing this, and any creature with line of sight to you has the chance to notice you.

Creating a Diversion: You can use Bluff to help you hide. A successful Bluff check can give you the momentary distraction you need to attempt to enter Stealth even if under observation.

Modifiers
Brightly-lit areas or noisy surfaces are difficult to negotiate stealthily. When you try to maintain Stealth in such situations, you incur the following penalties: "Standard" illumination includes the non-shadowy radius of a torch or lantern; "bright" illumination would include full sunlight or the radius of a daylight spell. Noisy surfaces would include scree, shallow bog, undergrowth or dense rubble, and very noisy surfaces would include dense undergrowth or fresh snow.

Likewise, noisy or poorly-lit areas make it easier to be stealthy. These bonuses are expressed as penalties to Perception, however, not as modifiers to the Stealth check. Targets who are distracted also suffer a penalty on Perception checks.

Characters who are blinded or deafened, or otherwise unable to see or hear, suffer a -10 penalty to Stealth checks. Characters who are both blinded and deafened suffer a -20 penalty to Stealth checks. This reflects their isolation from their environment and their lack of ability to compensate for environmental feedback.

Action
Entering Stealth is a move-equivalent action, but may be done as part of a move.

Taking 10 and Taking 20
You cannot take 10 or 20 on Stealth checks.

Special
Creatures larger than Medium suffer a penalty to their Stealth checks. Size Large suffer a -4, size Huge a -8, size Gargantuan a -12, and size Colossal a -16.

Creatures smaller than Medium gain a bonus to their Stealth checks. Size Small gain a +4, size Tiny a +8, size Diminutive a +12, and size Fine a +16.

If you have the Stealthy feat, you gain a +2 bonus to Stealth checks.

Masters of a cat familiar gain a +3 bonus to Stealth checks.

Some races have racial bonuses to Stealth checks; see the race description for details.

Hide in Plain Sight
So long as the requirements are met (e.g. a Ranger in natural surroundings, or an Assassin within 10 feet of a shadow large enough to hide within), characters who have the Hide in Plain Sight ability may re-enter Stealth even if under observation, and do not automatically leave Stealth when approaching an opponent from their facing squares.