Long ago, Rodvydel Castle fell into the evil grasp of Zeddas, who worked his foul spells upon the place to hide it from mortal eyes. Now you must walk these same haunted halls, trying to undo the harm this demon has wrought. Can you restore the castle? You must pit your own cunning against the fiend's treachery to unravel the sinister mysteries of this place. But beware - the King of Demons keeps a warm place ready for those who would meddle in his affairs!

Zeddas: Servant of Sheol is a first-person adventure game with pre-rendered backgrounds. The game is set entirely in the castle, which is a maze-like location that must be explored as the player searches for clues. The game's puzzles are predominantly logic-based; reading books in the library is often required to receive clues for their solutions.