Stephen R. Marsh

Stephen R. Marsh is an American game designer and lawyer best known for his contributions to early editions of TSR's Dungeons & Dragons fantasy tabletop role-playing game (RPG). Some of the creatures he created for the original edition of D&D in 1975 have been included in every subsequent edition of the game.

While attending high school in Las Vegas, Marsh began to play military boardgames. His interest led him to attempt to design what would now be called a roleplaying game based on his board games and using The Golden Bough as the basis for a magic system. However, he was unable to come up with a satisfactory system until he borrowed a copy of the recently published D&D rules from classmate Sandy Petersen. (Peterson would go on to create the Call of Cthulhu RPG in 1981.) After reading the rules of this new game, Marsh began to correspond with D&D co-creator Gary Gygax.

Marsh eventually sent his own vision of an elemental plane of water to Gygax, who changed it into a system for underwater combat encounters, and subsequently incorporated it into the Blackmoor supplement published in 1975. Marsh's material introduced several new aquatic creatures, including the sahuagin, ixitchitchitl, and catoblepas. Marsh also suggested a new character class, the mystic, that could teleport to various planes of existence via mental powers. Although the character class concept was not published, some of the mental abilities of the mystic were altered and then published in the Eldritch Wizardry supplement the following year as the first psionic powers for D&D. Marsh was not paid for his creative contributions to either of these rules supplements. Marsh was credited with "Special Thanks" on the credits page "for Suggestions and Contributions".

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