Concealment

Concealment prevents an attacker from clearly seeing his or her target. Concealment creates a chance that an otherwise successful attack misses (a miss chance).
Concealment provides defense against melee attacks, ranged attacks, melee touch attacks and ranged touch attacks. It also provides defense against some active combat feats such as Knockdown and Whirlwind Attack, however it does not defend against Feint, Disarm, Seeker Arrow or One Shot.
Concealment is applied as a chance to miss based on the level of concealment. Whenever an attack roll is made against a concealed target which would normally hit (ie, the roll matches or exceeds the target's armor class), a d100 is rolled. If the result of the roll is less than, or equal to, the concealment value, the attack misses.
The most common level of concealment, and the PnP maximum, is 50%, however spells like Ghostly Visage and Ethereal Visage provide lower values of concealment. The toolset allows for 100% concealment, so in theory one may also find higher levels of concealment in community modules.
==Methods of Gaining Concealment==
Player characters have the following methods of gaining concealment:
*Self-Concealment feats, 10% per rank of feat
*Monk's Empty body, 50%
*Assassin's Improved Invisiblity, 50%
*Shadowdancer's Shadow Evade, 5% to 25% depending on level
*Displacement, 50% (Bards gain 60%)
*Greater Invisibility, 50%
*Ghostly Visage, 10%
*Ethereal Visage, 25%
*Darkness, 20%
*Retributive Invisibility, 50%
Furthermore, invisible creatures are treated as having 50% concealment until they break invisibility; a blinded opponent will treat all targets as having 50% concealment.
==Concealment Countermeasures==
*The Blind Fight feat allows you a second roll if a concealment check fails.
*Seeker arrow and One Shot ignore concealment.
*Spirit Shaman's Weaken Spirits will remove it from spirits, and Ghost Warrior ignores concealment from enemy spirits.
*Doomguide's Ethereal Purge removes it from all creatures if they fail a save.
==PnP Comparison==
There are spells such as True Seeing and Blindsight that would counteract concealment in PnP but that functionality was not implemented in NWN2.