D&Dtools1

Benefit

As long as you have a 3rd-level or higher darkness spell available to cast, shadows and darkness appear to obey your will. As a standard action, you can direct these shadows to obscure the vision of one foe within 30 feet. If your target fails a Will save, its attacks have a miss chance equal to 5% per level of the highest-level darkness spell you have available to cast. This effect lasts until the beginning of your next action. Creatures that do not rely on sight are unaffected by this effect, and those with Blind-Fight or similar abilities can fight as they normally would. As a secondary benefit, you gain darkvision out to 10 feet. If you already have darkvision, its range increases by 10 feet.