An optional expansion for the Fortress of the Yuan-Ti module, with three new locations that can be reached via the portals in Castle Serastis: The Serpents' Graveyard, the Slavers' Grotto, and the Shrine of Primal Chaos. Description, followed by a tactical summary. Statted monsters include an Animated Yuan-Ti Corpse, Qualsarros (corpse creature yuan-ti halfblood archivist 6), Yuan-Ti Purebloods, Dolathuzar (half-deep dragon yuan-ti halfblood).