There are two sets of deities commonly worshiped among the peoples of the world, the Cthonic and the Empyrean. Cthonic (Greek for “gods of the underworld”) are the gods of chaos, and as such are generally not worshiped openly in civilized lands. Nevertheless they all have cults in various cities, towns, and villages, some secret but some open in the less lawful cities. Cthonic worshipers are also common among barbarian and humanoid tribes.
The Empyrean deities are the gods of law, and as such are worshiped openly and commonly throughout the civilized lands.
Individuals of a neutral alignment may worship either Cthonic or Empyrean gods, though this is usually determined by their cultural background. Those from more civilized lands will usually worship an Empyrean god, while those from barbarian or tribal backgrounds will tend to worship a Cthonic deity.