The Disciples of Dagon is a cult dedicated to Dagon which exists in the Hyborian Age. It consists of Deep Ones and humans whom have been transformed into fish people. In one of the possible futures that Conan of Cimmeria saw, he was the sole survivor of a wrecked ship. Who ended up in a sinister fishing town that was desolate and inhabited by fearful people. He was told that things had drastically changed for the worst in the last couple of months, with people disappearing.
He discovered that the Disciples of Dagon had infiltrated the town, when they attempted to kill or capture Conan and the barmaid he was with, sleeping in his room. They seized her and he pursued them underground, down the stairs. Where they were calling to Dagon, about to offer her to their god. He attempted to intervene but both Conan and the barmaid were taken by Dagon. Afterwards, his vision showed both of them now thralls of Dagon, physically alive but having experienced death of the mind.