Cthulhu-like Sanity Rules for Shoreline GURPS Collective

Gene Michael Stover

created Sunday, 2022 April 16 (version 0, strawman)
updated ???

This is https://cybertiggyr.com/sanity.html

What's this?

The third adventure from the Children of Lovecraft Country adventures relies on sanity so much that we need some sanity rules that resemble the sanity rules for the Call of Cthulhu rules.

The Call of Cthulhu rules tend to create a quickening spiral down into insanity if a character fails several checks in a short span of time. It would be nice to duplicate that.

Let's start with Roger Bell_West's Sanity for GURPS rules as suggested by Dustin, but I'm adding some clarifications.

Fearfulness

1. Let's create a Fearfulness counter. It starts at 0 for most characters. You want it to be low. (If some really excellent things happen to you, it might go negative.)
2. A fright check is now modified by your Fearfulness. (See the Fright Checks section for details.)
3. We could talk about Sanity as [IQ - Fearfulness], but we don't need to track it on the character sheet.
4. If Sanity is ever 2 or less, the character is insane & unplayable.

Fright Checks

There are two kinds of fright checks: Normal & Cosmic.

For a Normal fright check, do this...

• If you are Unfazeable, congratulations on being awesome.
• Start with normal fright check target: It includes your Fearlessness.
• Subtract your Fearfulness. (If Fearfulness is negative, it acts as a bonus.) That's your target value.
• Roll your 3d6.
• If you get target or less, awesome.
• Otherwise...
  • Check the Decreasing Sanity section because you might lose some sanity by increasing your Fearfulness.
  • Roll on our custom Insanity Tables for Cthulhu over GURPS to see how you react right now.

At the GM's discretion, we might be looking at a Cosmic horror fright check.

• Start with your IQ.
• Adjust it by your Cosmic Fearlessness. (Your normal Fearlessness does not count, & there is no Cosmic Unfazeable.)
• Subtract your Fearfulness. (If Fearfulness is negative, it acts as a bonus.) That's your target value.
• Roll your 3d6.
• If you make it & you haven't spent any points on Cthulhu Mythos knowledge, awesome! (Stop here. Don't do the next steps.)
• If you make it and you have Cthulhu Mythos knowledge...
  • Roll against your Cthulhu Mythos knowledge.
  • If you fail your Cthulhu Mythos knowledge check, then you're good. Stop here. (Yes, failing your Cthulhu Mythos knowledge check is good.)
  • If you succeed, use the amount you pass by as if it was the amount by which you failed your actual fright check. Look at the Decreasing Sanity section.
  • (Do not roll on the failed fright check tables. You aren't afraid... You're just a little less sane than you were a moment ago.)
  • (This approximates how, in CoC, more knowledge of the Cthulhu Mythos increases the rate at which you go insane.)
• Otherwise (you failed your fright check & don't have any Cthulhu Mythos knowledge)...
  • Check the Decreasing Sanity section because you might lose some sanity by increasing your Fearfulness.
  • Roll on the Failed Fright Check table to see how you react right now.

Decreasing Sanity

In the Call of Cthulhu rules, when you lose a fright check, you make another die role to see how it affects your sanity. (It usually lowers it.)

For example, in CoC, they might say that a character who loses a particular fright check loses “0/1d3 sanity points.”. That means that, if you failed by a small amount, it doesn't change your sanity, but if you fail by a lot, you roll 1d3 & lose that many sanity points. Sometimes the loss is temporary (like for the adventure), but sometimes it's permanent.

When you fail a fright check by 4 or more, let's increase Fearfulness by [amount_you_fail - 3]. So if you fail by 4, you increase Fearfulness by 1. Here's a table...

The idea is that changing your fearfulness by failing a fright check is rare, but as it occurs, the bell curve on those 3d6 die rolls makes it more likely & bigger, sort of like in the CoC rules.

Normal horror vs Cosmic horror

Normal horror is mostly about the mental shock from witnessing immediate physical dangers, though some other things fall into normal horror. Cosmic horror is about humanity's place in the universe.

Examples of normal horror are...

• gore, like body parts scattered on the road after an automobile accident
• gore, but it's someone you loved: Normal, but at a penalty.
• trapped in a sunken boat, & the water is coming in. You'll drown if you don't escape within minutes! It's normal horror, though possibly at a penalty because it's personal & there's time pressure.
• seeing a ghost

Examples of cosmic horror include...

• learning (or being reminded) that humanity's destiny is at the whim of uncaring, incomprehensible, semi-supernatural beings
• seeing a nearly incomprehensible demon or other thing from another world
• learning that the government has a mind control program. (Could go either way, but if you learned that, say, there was a Manchurian Candidate type of program & that, from what you know right now, you couldn't be certain that you aren't a Manchurian Candiate, then yeah, it's cosmic because it's about how you can't be sure of your reality or have control over who you are.)
• seeing one or two dead rise from their graves

An example of a special situation would be seeing an army of dead rise from their graves. It's cosmic because you're seeing the dead rise, but at the same time, it's normal horror because it's a hostile, overwhelming force. So make both horror checks. Right now! 8-)

Cthulhu Mythos Knowledge

It's not the same as regular occult knowledge or forbidden. It's a specific skill.

Cthulhu Mythos knowledge is dangerous! That's why it affects cosmic horror fright checks.

Recoverying Sanity

Recovering sanity is the same as reducing Fearfulness.

You lower Fearfulness by 1 point every 6 months that you have no adventures & no personal hardships. In other words, if you live a boring life for 6 months, you lower Fearfulness by 1 point (but never below 0).

If you spend 1 character point, devoce an in-world month to it, and have an in-game explanation such as psychotherapy, meditation (with a guru helping you), or a vacation (with no adventuring!), you lower fearfulness by 1 point (but never going negative). (This is what's suggested in Roger Bell_West's Sanity for GURPS.)

You can buy Fearlessness or Unfazeable with character points as normal.

Change Log

cybertiggyr.com

Copyright © 2022 Gene Michael Stover. All rights reserved. Permission to copy store, transmit, and view in electronic form is granted. Permission to link to this document is granted.