Dagon, known as the Drowned God, is a demon from the Abyss, whose domain is the drowned dead, and the evil creatures of the watery depths. His minions are known as “Those Who Sleep Below”. He is said to bestow nightmares upon those who swim in the Sea of Fallen Stars and its tributaries (including the Moonsea). He is sometimes depicted as a tentacled humanoid with the head of a many-fanged fish.

In an attempt to achieve godhood, Dagon once began a campaign of slaughter against the shalarin - a race of aquatic humanoids - until his plan was thwarted by the merfolk of the Sea of Fallen Stars.

A culthood of Dagon persists along the northern shore of the Moonsea, and shrines to him are dotted along the coast, most often in caves on the shoreline. Followers engage in activities such as wrecking of ships, human sacrifice, and the summoning of monsters from the depths.