Faithless

The Faithless are mortals who do not have a divine patron. This could be because the mortal never worshiped a deity (or rejected outright the worship of any deity), the mortal's divine patron has died, or that their divine patron rejected them for whatever reason. A soul who does worship a deity but did not sufficiently uphold their patron's dogma is instead judged False.

A Faithless soul receives only one sentence when it reaches the City of Judgment on the Fugue Plane: the Wall of the Faithless. The soul is bound onto the wall by a green mold that binds the Faithless (and only the Faithless) to the wall. Over time the soul dissolves into the very substance of the wall.

Demons propagate by stealing Faithless souls from the wall and retreating with them back to the Abyss.

Other References
The video game Neverwinter Nights 2: Mask of the Betrayer presents the player with the option of forever destroying the Wall of the Faithless, so that the Faithless no longer endure any punishment in the afterlife. According to the game, destroying the Wall destroys part of the covenant between gods and mortals: the game engine thus interprets the Wall's destruction as an evil act, even though it is more a Chaotic act.

Destroying the wall grants the player a god power called Spiritual Evisceration, it can be used an unlimited number of times per day and instantly devours the spirit of any (with exception to Greater Deities) enemy it is used upon. Exporting the character prior to the end cinematic will allow this power and all other spirit-eater powers acquired with the character to be carried over to a new game.