So taking a leaf from Call of Cthulhu, the main difficulty with rituals... well, the main difficulty in addition to the moral and logistic problems inherent in most Carcosan rituals, is the time required to study all that weird text and understand and learn it well enough to be able to perform it properly. I think I'll say 1 week per attempt to learn a ritual. As with other "skills", learning a ritual will have a 2 in 6 chance of success, modified by INT, and can be retried over and over, if a PC wants to.
In addition to having a high INT, two other factors are relevant. Jale Men get a +1 bonus, as do those with the arcane lore talent.
Other than that, all the rituals in the Carcosa book will operate exactly as described therein.
Now, the second point of interest is that I want to also allow all the rituals from Call of Cthulhu to be (potentially) accessible to PCs as well! This was an idea that struck me as I was reading Carcosa -- how I also have this other book on my shelf (CoC 30th anniversary edition) which has loads of cool creepy rituals which would fit right in with Carcosa. They're a lot lighter on the human sacrifice, but their effects are generally less far-reaching as well. I thought that the two types of ritual would nicely complement each other.
The only trouble is that D&D (or Mutant Future, in this case) is a different beast than Call of Cthulhu, mechanically speaking. Conversion time!
(CoC veterans, please forgive and correct my ignorance if anything I write here is totally wrong! I'm just going from having read the CoC 6th edition rules, but never having played a game with them...)
Here's what I was thinking:
- When a ritual specifies a loss of magic points, this translates to a loss of hit points. A nice simple system, which fits well with the D&D trope of PCs gaining more hps (and thus being able to use more magic) as they go up in level. I also like the idea that by using some types of magic you are actually risking your own life.
- Rituals which specify a loss of sanity result in an equivalent (but temporary) loss of WIS. WIS lost in this way would be recovered at a rate of 1 point per day or week or something.
- Rituals causing a loss of POW (which is permanent, as far as I gather) result in a permanent loss of WIS.
Other than that, I think the CoC rituals should work pretty much as written in a D&D environment.
So, that concludes my Carcosan chargen rules. Mix that lot in with Jeff's "what went wrong" doc and I think we have a nice old-school system mash-up on our hands!
I'll probably put all this together into a PDF at some point, for use in my planned Carcosa session(s), and for the reference of anyone else who decides to go down a similar route!
ps. That was my 200th post on this blog! Crikey, that went quickly!