Running an adventure with a gothic or lovecraftian core has crossed the mind of most DMs, but effectively incorporating this type of narrative to D&D games has it’s own challenges. Humor and the parodying fantasy tropes are a fundamental part of most fantasy RPG tables, and this clashes with the intended tone of such campaigns. Asking for the player’s cooperation in carrying the mood before starting
is important, but the heavy lifting will have to be done by the DM. Kobold Press posted a series of articles with suggestions on how to manage the mood at a table, Don’t Look Now: Handling Fear and Suspense in Fifth Edition:
Good discussion among forumers in the Minmaxboards,
touching on topics like the problem with powerful characters where
helplessness is desired, the need for players cooperation towards the mood, and the
possibility of the DM rolling Stealth rolls to promote uncertainty.
And of course, a good soundtrack can make the difference, so check out my Sounds and Music post with tips for that.