Call of Cthulhu Role Playing Game

Call of Cthulhu is a horror fiction role-playing game based on H. P. Lovecraft's story of the same name and the associated Cthulhu Mythos. The game, often abbreviated as CoC, is published by Chaosium. It has won several major awards.

The players take the roles of ordinary people drawn into the realm of the mysterious: detectives, criminals, scholars, artists, war veterans, etc. Often, happenings begin innocently enough, until more and more of the workings behind the scenes are revealed. As the characters learn more of the true horrors of the world and the irrelevance of humanity, their sanity (represented by 'Sanity Points', abbreviated SAN) inevitably withers away. The game includes a mechanism for determining how damaged a character's sanity is at any given point; encountering the horrific beings usually triggers a loss of points of SAN. Also, to gain the tools they need to defeat the horrors - mystic knowledge and magic - the characters must be willing to give up some of their sanity.