Darkness

Darkvision allows many characters and monsters to see perfectly well without any light at all, but characters with normal vision (or low-light vision, for that matter) can be rendered completely blind by putting out the lights. Torches or lanterns can be blown out by sudden gusts of subterranean wind, magical light sources can be dispelled or countered, or magical traps might create fields of impenetrable darkness.

In many cases, some characters or monsters might be able to see, while others are blinded. For purposes of the following points, a blinded creature is one who simply can’t see through the surrounding darkness.

A creature blinded by darkness can make a Listen check as a free action each round in order to locate foes (DC equal to opponents’ Move Silently checks). A successful check lets a blinded character hear an unseen creature “over there somewhere.” It’s almost impossible to pinpoint the location of an unseen creature. A Listen check that beats the DC by 20 reveals the unseen creature’s square (but the unseen creature still has total concealment from the blinded creature).