Blind Fight

Note: Blind Fight increase your chance of hitting conceal created by 50% of their concealment value. Meaning if a opponent self-cast Displacement (which gives them 50% concealment) their concealment value is reduced to 25% because you get a second attack roll against them for every swing. If a fighter-type (who can attack up to 6 times per round) tried to fight the opponent without Blind Fghter, over half their attacks would miss. This means you would miss 3 attacks of 6 under concealment.(Which doesn't include AC) Yet, with this feat, you would land 4 out of 6 hits.

It does not increase damage, but increases your chance your to hit with an attack. Though it's a VERY good feat, it's usefulness depends on the server or module as well as the class. For example, a Fighter, Rogue, and Ranger, in a undead server would find this feat useful since they can only do damage through physical attack; meanwhile, a Paladin, Cleric, and Wizard would not have much use for it. An example of undead with conceal, would be a Wraith, which can be turned by a high level Paladin with a high Charisma score. The same method can be use by the Cleric, however, both a Cleric and a Wizard can use spells to put down the Wraith so blind fight effectiveness (or need) is reduced in this scenario.

Blind Fight does not guarantee a hit against concealed opponents, it does not increase damage against concealed opponents, and it does not make you immune to flanks. It simply reduces your miss chance against a concealed opponent.

External resources

 * NWNWiki:Blind Fight