What Are the Deep Ones?

The Deep Ones are a long-lived, amphibious species, part fish and part frog in the witnesses' descriptions, that live in cities on the ocean floor. The Archive files them as a species with a regional threat: their business is with the human communities of certain coasts, and their main known settlement lies off Devil Reef, a mile and a half offshore from Innsmouth, Massachusetts.

The bargain

What distinguishes them in the record is that they trade. The account of Innsmouth documents an arrangement under which certain coastal families interbred with the Deep Ones in exchange for prosperity: gold, good fishing and protection. Captain Obed Marsh is the name the account gives for the original agreement. The children of these unions appear human in youth and take on Deep One features as they age, the "Innsmouth look" the account describes, until they go down to the water and join their kin. The oldest families of the town are understood by their neighbours to be waiting out something considerably longer than a human lifetime.

What they worship

The Innsmouth account has the Deep Ones paying homage to Dagon and to Cthulhu, both of which have dossiers of their own. They are not themselves the subject of that worship, and the Archive keeps the two apart.

Where else they appear

A second chronicle on file, The Thing on the Doorstep, reaches into the same family line: the household at Arkham in which that account is set was joined to an Innsmouth family, and the Archive files the Derby house under this dossier for that reason. The account has been adapted twice for the screen, once as Cthulhu in 2007 and once as The Deep Ones in 2020, both with the setting altered.

For where Innsmouth is, why no atlas carries it, and how the Field Survey pins the reef, see the Dispatches below.