The Fortress of the Yuan-Ti describes a fortress build into a cliff side and the slave village outside. The Adventure is the third of three but can easily be played by its self. The adventure revolves around the players discovering the dark plot to revive the demon Sertrous and then stopping it. The adventure describes the outside, inside, and hanging towers of the fortress. The adventure concludes in a forth extra-planer tower were you fight the boss. It also includes 4 sidetracks from portals that explain how they get the materials for the ritual. Final part of the Barrow of the Forgotten King series.