Obed Marsh was a sea captain from Innsmouth. At the height of his career he had command of three ships, the Columbia, the Hetty, and the Sumatra Queen. He learned from the inhabitants of a Polynesian island a ritual to summon the Deep Ones. This was done on Devil Reef before entering into a pact with them, offering human sacrifices in exchange for a constant supply of fish and the occasional golden artefact. Marsh at some point founded the Esoteric Order of Dagon. He died in 1878 and his family continued their control of Innsmouth. He is the great-great-grandfather of Robert Olmstead.