Page "Call of Cthulhu (role-playing game)" Paragraph 3

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 SAN points.

To gain the tools they need to defeat the horrors – mystic knowledge and magic – the characters may end up losing some of their sanity, though other means such as pure firepower or simply outsmarting one's opponents also exist.