Far, far to the south, where east and west meet and become north, there is a valley, carven not by the slow slide of the world's rocky skin over her firey heart, but rather the wind and water have carven it, deep and narrow, folding away from the sun. Here, at its deepest depths, the Light never reaches. Here, at the top of the bottom of the world, lies the place which Shadow and Darkness have dedicated to themselves.
Darklings are a kind of Halflings living in the sewer of medium to large cities.
Even though they smell badly and are quite dirty, Darklings are friendly and clever.
They try to limit the knowledge about their existence to only a small number of trustworthy persons, including player characters.
Darklings trade in information. Money, weapons and magical items have no value for them. This is why they hide beneath the sewer grates, listening to all that is said in the city above.