Cover And Concealment

Combat Overview

Two mechanics limit an attacker's ability to harm a target: cover and concealment. Cover is physical obstruction — a wall, a table, another creature — that improves AC and Reflex saves. Concealment is impaired visibility — darkness, fog, invisibility — that introduces a random miss chance. They are independent: a target can have both, either, or neither.

Cover

Cover applies when a straight line from the center of your square to the center of the target's square passes through a wall, pillar, or other solid obstacle. The GM determines whether cover applies and what degree.

Cover Type	AC Bonus	Ref Save Bonus	Notes
Cover	+4	+2	Standard cover — half or more of the target is blocked
Improved Cover	+8	+4	Also grants Evasion against Reflex-based area effects; GM discretion
Partial Cover	+2	—	Less than half the target is blocked; no Reflex bonus
Total Cover	Cannot be targeted		Target cannot be attacked at all from that angle
Soft Cover	+4	—	Intervening creatures (allies or enemies) provide cover against ranged attacks only; no Reflex bonus; does not grant Improved Cover

Cover and spells. Cover does not apply to touch attacks or ranged touch attacks unless the cover is between you and the target in the strict line-of-effect sense. Total cover also blocks line of effect, which prevents targeting the creature with a spell entirely — not just adds a bonus.

Concealment

Concealment applies when a target is hard to see clearly — dim light, fog, smoke, or magical darkness. It does not improve AC; instead it introduces a miss chance on attacks. Roll the miss chance after a hit is confirmed; if the roll falls within the miss range, the attack misses regardless of the attack roll.

Concealment Type	Miss Chance	Common Sources
Concealment	20%	Dim light, light fog or smoke, blur spell, partial invisibility
Total Concealment	50%	Darkness, heavy fog, full invisibility, target out of sight entirely

Invisible Attackers

Attacking while invisible grants total concealment — 50% miss chance against you.
You still need to locate the target; if you guess wrong square, you automatically miss.
Invisible attackers gain +2 on attack rolls (target loses DEX bonus to AC and is effectively flat-footed against you).

Beating Concealment

Blindsight ignores concealment entirely — the creature perceives without relying on sight.
True seeing (spell) negates concealment from invisibility, blur, and displacement.
Precise Strike and similar abilities require the target not to have concealment.

Stealth and Concealment

The Stealth skill requires concealment (or cover) as a prerequisite to hide. You cannot make a Stealth check in plain sight with no cover or concealment unless you have a special ability allowing it (such as Hiding in Plain Sight).

Moving while hiding	You can move at half speed with no Stealth penalty; moving faster imposes –5 (normal speed) or –20 (running) to your Stealth check
Sniping	After making a ranged attack from hiding, you take a –20 penalty on Stealth to re-hide; success means the target doesn't know your location
Distraction	You can use Bluff to create a distraction, allowing a Stealth check even when observed (one attempt per observer per encounter)

Flanking Surrounding a target from opposite sides grants +2 on melee attack rolls and enables Sneak Attack.

Flanking

Coup de Grâce

A coup de grâce is a full-round action that automatically hits a helpless defender (one that is bound, sleeping, paralyzed, unconscious, or otherwise unable to act).

Action	Full-round action
Hit	Automatic — no attack roll needed
Damage	Roll damage normally, including a critical hit (as if the threat were automatically confirmed)
Fortitude save	DC = 10 + damage dealt; failure = instant death
Ranged weapons	Only if the target is adjacent
Spells	Spells that deal damage can be used for a coup de grâce; those that don't deal damage cannot

Provoking an AoO. Performing a coup de grâce provokes attacks of opportunity from any threatening enemy — a helpless creature's allies may interrupt before the killing blow lands.