How do you use Cthulhu Mythos?

[Gladius]

Typically, (esp. if you're using a prewritten module), there's specific lore/information available if a player does research, finds a mythos tome, etc. But how do you *use* the Cthulhu Mythos skill?

It seems to be the "holy grail" of skills for players - it's hard to come by, and my players, at least, are often asking to make Mythos rolls. The problem is, there isn't often information to be given when they want to use it - the information is either hidden somewhere in the tome that they will have to read, or uncovered in some other way. Sometimes I'll dig into my copy of Dan Harms' Encyclopedia Cthulhiana for some bit of lore, but sometimes this sends them off onto a tangent.

I want the skill to be useful to them, since it is so hard to get (and is often very low %, so if they do make the roll, I want it to be worthwhile), but I don't want to give away the plot, or give them the "secret password" to get into the cult HQ (or whatever).

How do you use the skill?

[Keeper Jon]

This is a good topic for the show, but I tend to use the Cthulhu Mythos skill as deeply hidden recesive memories. And when an investigator encounters a Mythos entity it's almost like a shock to their mind that might "dislodge" a small piece of information that has been bred into the human psychie over thousands of years of evolution. The investigator won't know why he knows a certain thing, he just feels certain that he's right about a factoid or something.

[Keeper Dan]

Indeed, it's an excellent topic. Mainly because there are so many ways for the Keeper and Players to work the skill.
There are two ways of getting it, bouts of insanity and reading tomes. Jon's method (which I've also used) seems to be connected to the insanity method of gaining the skill. Reading about it in books would grant more specific info that can be researched, but the insane insight is just what happens when someone's brain has gone thunk when a cog got loose. If this is the only way a character has gotten the skill, then I'd give more loose insights, like "you're not sure why, but this thing really hates light". Where as if Mythos was gained by reading, then I'd say it like "The texts you read described something very much like this, and apparently there was a case where someone managed to drive it off using a large torch". Was it the light or fire that did it? Experiment and find out!

[Dr. Gerard]

This is such a good subject, and I've found it comes up a lot in games. In general, I find that some players like to ask for a Cthulhu Mythos roll anytime they're faced with strange evidence. And it's hard to just dismiss their curiosity. But as you say, a scenario would almost never hinge on a successful CM roll, because the skill rarely gets much above 20% in my experience before death or insanity takes them out of the game. So you can usually expect failure on those rolls -- but you can't depend on it! If you allow a roll, you have to be ready to handle extraordinary results! It would also be a pretty terrible cheat for such a roll to reveal the whole plot. It's a quandary.

I tend to be conservative with CM rolls. I tend to tell players that I will let them know when a CM roll is called for, and promise I won't wait for them to ask. I think players just want to cover all the bases. They tell you they're searching under the bed so they get to roll for Spot Hidden. They ask if a PC seems like he's telling the truth so they can roll Psychology. If they think they might otherwise miss some supernatural insight, they ask for an Occult roll. If they think getting a Mythos roll will help them find another piece of the puzzle, they'll ask as often as they can. I would discourage players from thinking Mythos should be part of their investigative checklist. That's the easy way out.

On the other hand, there are more creative ways to handle this, but they take some forethought. Jon has talked about a scenario in which he placed a "bonus" clue that added context to the story but was essentially a dead end. I like that approach. But it's tricky, and hard to do on the fly. You'd have to come up with an interesting Mythos insight ahead of time that is also clearly a dead end instead of another plot hook or piece of the current investigation puzzle.

I like to make sure any Mythos insight is somehow connected to the story that the characters have lived. So the only Mythos insight they would get on a particular check would have to do with whatever their current Mythos skill had come from. If it was a book about Hyperborea, then the insight would have to be related in some way to that part of the Mythos. Likewise if it was a book about witches in Massachusetts. The thing is, it's hard to give players anything that mentions a name or location or even folklore without accidentally encouraging them to follow it as a clue to its logical end.

So, perhaps using this technique means actually allowing the scenario to derail into a tiny one-session side adventure if they make a Mythos roll AND they decide to follow the information to its logical end. To my taste, I would want to make it very clear that any Mythos insight is a double-edged sword, and that following their noses on such a clue could land them in trouble. Almost like the Push mechanic we're talked about -- you could foreshadow a certain sense of doom that signals to the player that there is a terrible bargain before them. Red pill, or blue pill?

A shortcut way to handle this might be to look for a published side adventure, if available, in the setting you're using. Let's take the Kingsport sourcebook. It references all kinds of little side items that come from HPL's fiction. Perhaps a successful Mythos roll gives them info about dark rumors surrounding 306 Summit St. If they decide to go, they're likely to run into worm-ridden Solomon Oaks or his horrific undead "dog" Cerebus. But basically stop the adventure there, a dead end with no further clues, or provide a clue that gets them back onto the main plot, like a structural detour. If you really wanted to derail your plot, give the players clues about the Green Flame and the Kingsport Cult and off they'll go on a whole other investigation. I don't recommend giving out too many plot hooks at once. I made that mistake. What happens is the sanity losses contained in each plot start to stack up, and since the sanity recovery doesn't happen until one plot is resolved, you could be driving PCs into a kind of TPI -- Total Party Insanity. So, use caution, and resolve detours quickly.

I haven't used Jon's intuitive suppressed memory technique, though I might in the future with some tweaks. This approach would make sense to me if there was a heavy dream element in the scenario, so you could say this insight came to them in a dream and they can choose to believe it or dismiss it. You could also use flashbacks, where the character remembers a scene that happened before the in-game timeline, which is a technique that a few scenario writers are starting to use and I think has some interesting potential.

Anyone else have ideas about how to offer interesting Mythos information that isn't likely to derail?

[KeeperMurph]

This is getting so much attention let's cover it as a side topic tomorrow on the show. I want to do it then rather than later before it loses momentum.

[Keeper Dan]

Works for me.

[fox01313]

Been seeing this a lot lately on a few online games, granted the one online campaign I'm thinking of has been run a little loose with some gaps of common sense where players are asking to roll this skill (over other skills that you can increase with a successful roll) as well as educated investigators expecting someone under the year of 8 to have the same amount of knowledge as an adult when hunting for clues. Been a while since hearing the MUP covering it so will listen to it again at work but I feel that Trail of Cthulhu put this skill write up the best of just having it as a skill where you have all the pieces roughly together & Cthulhu Mythos roll to connect the dots to all going to one mythos threat.

Of course the threat I remember in Trail (about using this skill could result in more sanity/stability lost) makes me more hesitant to ask to roll this skill & hope others do the same, it's fine for the keeper to ask for it but players should just avoid wanting to use it. Personally I'd rather go with some normal skill I have 10-20% in getting as default over most of the time being <10% for mythos which just feels like knowing 2 facts on a vast number of items in a particular subject.