The Doomsayer's Guide to Horror is toolkit for running Best Left Buried that builds on the basics presented in the Cryptdigger's Guide. It contains guidelines and procedures for running games, including advice for creating dungeons and a toolbox of alternate rules. Also includes Doomsayer facing lore and randomisers for the Thirteen Duchies of Lendal, as well as a new hexcrawl adventure, The Lowlands of Internment.