Oh, the Insanity!
I had been reading through a few Call of Cthulhu RPG message boards recently, and the idea of a sanity mechanic just keeps coming up. It is, as far as I can tell, a means of determining a character's actions in the face of a completely unexpected and unwanted reality. CoC builds it in to their system, and other systems that try to emulate the setting either develop their own Sanity rules, or ignore them altogether.
I have, at times straddled the fence, wavering between ignoring them and finding a use for them. A cursory reading of Lovecraft's Mythos reveals that the protagonist's hold on sanity is tenuous at best, and rules governing sanity are almost a necessity to effectively playing the setting.
However, my system of choice is Risus: The Anything RPG by S. John Ross. Characters are built using cliches, essentially a short descriptor of abilities, motivations, skills, preferences, etc. The simple mechanic calls for checks against the various cliche levels in a character. Combat is resolved by characters rolling the appropriate cliche levels against an opponent's appropriate cliche level.
One could tack on a mechanic that would replicate the Sanity rules of CoC, but in the end I think this just muddies the overall simplicity of Risus. Others have attempted to write rules for implementing Sanity into a Risus version of CoC to varying success. I have even attempted something similar.
But, as I think about it, the answer has already been built into the system, without me having to do a lot of tinkering. It is all in the way Mssr. Ross designed Risus combat. Allow me to elucidate:
The mechanic is predicated on two of the underpinning philosophies of Risus combat:
1. Combat is essentially wearing the opponent down or jockeying for position; and
2. The winner gets to decide what happens to the loser.
In other words, in a combat situation, when one combatant wears another to zero, the victor can determine what happens to the loser all the way from outright death to simple incapacitation. It is the possibility for incapacitation on which my take on the insanity rules hinge. Let's use Lovecraft's story The Call of Cthulhu itself as our framework. The protagonist comes face to face with the Big C. At that point, the GM can decide between two different directions in which to take things: One is the Single-Action Conflict (page 4, Risus Rules), wherein Great Cthulhu rolls his Unimaginable Horror from Beyond the Stars (8) cliche versus the PC's Inquisitive Investigator (3) cliche. High Roll wins. Chances are, Cthulhu wins that roll. In that case, he gets to say what happens to the investigator, and the most appropriate result is that the investigator passes out and reawakens in a cushy white room where all the walls are upholstered. Perhaps the investigator survives his first glimpse of Cthulhu, and a fight ensues. As they battle, The Investigator is worn down to zero dice and effectively loses the battle. Again, the GM may determine that the PC is now incapacitated by a complete break with reality.
GM's who plan an extended campaign romping through Lovecraft's Mythos might find this system works better for short scenarios. This is a simple way to resolve the questions of how to work CoC's sanity mechanic in a Risus setting. After all, I'm all about simple!
However, after discussion on the RisusTalk list, on the next page there is an alternative, though similar, system that should work for longer campaigns.
Proceed to Even More Insanity!