Fortress of the Yuan-Ti involves evil yuan-ti who conspire to destroy a kingdom using dark rituals and the bones of a long-dead king. The player characters must storm the yuan-ti fortress and take the bones from the cultists before they complete their rituals and unleash a far greater menace upon the world.

Fortress of the Yuan-Ti was written by Ari Marmell, and was published in September 2007. Cover art was by Steve Prescott, with interior art by Dave Griffith.