Applied Mechanics: When, and Why, to Kill Player Characters (CoC 7th ed.)

In which I come face-to-face with my killer instinct...

I have a confession to make. 

I've never killed anyone. 

Well... that's not totally true. As a Keeper (and GM in other systems) I have decreed dozens of unpleasant demises for a host of NPCs, often for no greater reason than to help add some atmosphere to a session.

But, in the couple of years that I've been regularly running RPGs, I have never killed off a player character. I have never, in fact, even "attempted" to, to the fullest extent that the rules permit. Certainly I have written RPG scenarios and adventures that offer the option of a high lethality rate, but when I'm actually sitting at the table I have never been able to pull the trigger.

I can offer a variety of excuses, we can probably get real Freudian about this, but the salient point is that when I run an ongoing game, I come to like the characters, and I want to see them survive the adventure and move on to the next one. I don't want to kill a character off.

But you've got to be cruel to be kind, right?

Nick Lowe knows what's up. 

(The cover art copyright is believed to belong to the label, Radar Records, or the graphic artist(s).)

This is, I think, especially true in Call of Cthulhu. The one thing that everyone knows about this game, if they know anything about it, is "Everybody goes insane and dies, not always in that order." This is not actually an accurate statement, and in fact this is not even really the goal of most modern-day Call of Cthulhu experiences. However, it is so baked in to the existential being of the game that to run a game without at least the realistic threat of death and insanity is, in many minds, to fail to deliver the "authentic" CoC experience.

In talking to my players, listening to great authorities like the Good Friends of Jackson Elias, and reading some scenarios I'm fond of, I have come to accept that the nearness of death and madness are needed to create the right kind of stakes in this game. The underlying stakes in a CoC session are usually very clear: You will try to find out what is going on, and if you make a foolish mistake, you will die. If you make no foolish mistakes, you will probably lose your grip on reality. There is no way to win, in the long term.

(This, by the way, is a good fit for the "stale beer" genre of spy fiction I was talking about in the previous post. The best you can do is to do your job, until you learn something that winds up killing you.)

However, I don't want to dish out death all willy-nilly. Part of what has kept me from turning on the mortal danger in a session is that I didn't want the players' characters to die in an unsatisfying way - by accident, say, or at a time when there was no particular danger. On the other hand, I didn't always feel I had a great way to know, mechanically, the level of danger that the PCs were walking into.

In the rest of this post, I'll be talking about the philosophy and mechanics of when, why - and how - to kill or indefinitely disable player characters. As part of this discussion, I give an example from the popular scenario "Edge of Darkness", and assess each of 3 major encounters in it regarding their likely lethality and how well that fits into the narrative structure.

Game Philosophy: Lethality Helps Raise Tension and Reinforce the Game's Feel

I've been giving some thought to the theory and mechanics of when, and how, I might go about killing off my players' Investigators. Or driving them mad. The net result of death or indefinite madness is basically the same - a Player has to roll up a new Investigator.

Your approach to this question as a Keeper (or DM, or GM, or Storyteller...) is going to do a lot of work for you in terms of helping build the world you want your group to play in. If death is too hard or too easy to achieve, it creates a different kind of experience than what Classic Call of Cthulhu is going for. Not necessarily worse, but different.

As I reconcile myself to the idea of bringing Investigator deaths into my game, here are my two guiding principles:

1. I want player character deaths to be meaningful. 
This is really a specific application of a broader rule that I'll talk about another time, and which I think everyone agrees to in theory if not in practice, which is that all risks should be meaningful. Call of Cthulhu is pretty good about avoiding "stupid" deaths, such as a fumble on an otherwise low-risk roll that somehow snowballs into a character's death. In real life, people die for stupid reasons all the time, but real life isn't an inherently narrative experience (unless you subscribe to the Tao of Pratchett).

In practice, the golden rule I'm following is this: I don't want to call for a roll with potentially fatal consequences unless the action is at a moment of high tension. 

2. I want players to choose to engage with potentially lethal situations.
Sandy Petersen (and others, of course) makes an excellent point in his recent talk about building horror scenarios: You really don't want your Investigator to open an otherwise innocuous door only to have a shoggoth jump out and devour him. It's cheap, and ultimately it sends the wrong kind of signal about the world you're playing in. (Again, we'll talk more about these ideas in a later post).

He recommends - and I agree - that before you spring a potentially lethal trap on your Investigators, they should be given ample warning. A smear of blood or gobbet of flesh on the threshold of a cave; the quavering, half-intelligible testimony of a frightened local rustic; a worm-gnawed tome of ancient wisdom that gives tantalizingly vague descriptions of an ancient evil. These are signposts that you use, as a keeper, to say to the players: "Hey - this is going to be potentially painful for your Investigators. If you proceed, you're signing a waiver, and things will get real around here."

If the Investigators press on, their players are tacitly accepting your bargain - and knowing they're entering a lethal situation increases the scenario's tension. This is one of the main issues I have with the caricature of CoC as an "all-death-and-madness-all-the-time" game: such a game would have a real problem building tension. If you can never succeed or survive, then in the best case you risk slipping out of the Lovecraftian horror genre and into something like Paranoia-style nihilist comedy. In the worst case, of course, you risk having a boring game.

So allowing players to choose to enter a lethal or maddening situation is a big part of what adds tension and risk to our game.

And in order for a player to choose, they must understand what's on offer (via the signposts you, as a Keeper, give them), and they must be willing to risk their Investigator - meaning, in fact, that the encounter must have at least the slim possibility of survival. A sliver of hope - of false hope, sometimes - is often all that's needed to get an Investigator to go into a situation that promises almost certain death. Almost certain death or madness is quite a far distance from certain death, after all.

From the Keeper's perspective, then, you need to be able to tell how deadly a given encounter is going to be for your Investigators, so you can provide the right message to your players, so they can make an informed choice. If it's a low-risk encounter, you can spring it on them with minimal warning. If it's a potential or likely total-party-kill, you'll want to put down the narrative equivalent of a big flashing neon sign saying "CERTAIN DEATH ----> THIS WAY!"

The next section provides a quick-and-dirty way of assessing the threat. It's something I plan to incorporate into the scenarios I write in the future, and something I'll use in my own game prep going forward. More on that in the upcoming After-Action Report for "Edge of Darkness."

Game Mechanics: How easy is it to die or go insane in this game, anyway?

Working through game math is one of life's little pleasures, isn't it? If you'd like to see my very back-of-the-napkin calculations for the likelihood that an average Investigator (with a maximum of 11 HPs) survives an encounter with a variety of weapons and monsters, scroll down to the bottom. Do not fear: the math will be clearly marked as such.

At some point in the near future I'm going to try to create a "Lethality/Insanity Estimator" spreadsheet for use in Call of Cthulhu 7e. I will post about it later, when it's ready, or when I throw my hands up in bafflement and failure.

Why do we want to know how potentially lethal a situation is? A couple of reasons:

• At a global level, to get an idea of how lethal and madness-inducing CoC is as a game
• When designing or reviewing a scenario, to predict roughly how dangerous the monsters, Mythos entities, and other challenges will be to the typical Investigator.
• When running a scenario for your own table, to be able to adjust dice rolls on the fly in response to the number of Investigators at your table, and their condition going in to the encounter. This can help you maintain the narrative flow, tension, and payoff you're looking for.

Let's do an example of how lethality works, or doesn't work, at various places in the scenario. We'll use some of the Investigators at my table, and the scenario they're engaging with, "Edge of Darkness."

There are really only 3 or 4  times when an Investigator could conceivably die in Edge of Darkness, and the first one is very unlikely:

• Encountering Red Jake, everyone's favorite table-leg-wielding hobo
• Sticking one's head up into the attic, like an idiot
• Fighting a zombie (zombie Maggie, zombie Jake, or a zombie bear)
• Being attacked directly by the djinn/Lurker if someone is stupid enough to break the pentagram on the floor, or cross into the circle

When I ran the scenario (more on this in the After-Action post), I didn't want the Investigators killed by a hobo with a table leg, so I gave my Investigators a lot of chances to decide to talk him down (which they did). As it turns out, I didn't need to worry so much about it.

Red Jake: Low Lethality

If an Investigator wanders into the basement without checking his corners, Red Jake will assault him with the aforementioned table leg, and will get a bonus dice for a surprise attack.

However, even with a bonus die for surprise, his table leg only hits for 1d4 - not a great feeling, if you get your face beaten in, but not lethal, especially with allies nearby to bail you out. An unlucky Investigator might get knocked unconscious (be reduced to 0 HP) in 3 combat rounds, if Jake gets max damage each time, and the Investigator fails to dodge or fight back each time, but it's unlikely. However, it definitely could sting.

Assessment: Red Jake is a pretty good jump scare, and a good reminder of the dangers of poking around a creepy old house without checking your corners. 4 HP or so is a reasonable price to pay to learn that lesson. This is a little bump in tension, without derailing your scenario with a character death. It fits well here in almost all circumstances.

Poking a Head Through the Trap Door: High Lethality

If an Investigator sticks their head through the trap door into the attic, the Lurker will attempt to claw them to death and/or rip their heart out.

The Investigator can make a Dodge roll and just fall to the floor, losing (on average) 2 HP - not so bad.

If they miss that roll, though, they take 1d8 + 1d6 damage (on average 8 HP), plus another average of 2 for the fall - so that's 10 HP, on average. In fact, we would expect this attack to outright kill the Investigator (by taking all of their HPs at once) almost two thirds about half of the time (edited for math error)!  If they survive, they will almost certainly have a major wound, and perhaps be too injured to contribute in any meaningful way for the remainder of the scenario.

So now we need to ask ourselves: is this an appropriate time in the scenario to kill an Investigator? I don't think so, but others may disagree. There have been signposts in the adventure - Merriweather's journal, and (if they've found it) Marion Allen's letter both mention that the monster is in the attic. So it is a foolish move to go poking around up there, and I could understand if another Keeper decided to leave it as-is as a way to show what happens to foolish Investigators.

BUT - the real climax of the scenario is in the ritual at the end, which is a fun, participatory experience for all of the players. To kill someone off during the Investigation phase of the scenario seems sub-optimal - though the writer of the scenario anticipates this, and talks about ways you could bring in a replacement before starting the ritual.

Assessment: A dangerous encounter, properly signposted - but I think it comes at the wrong place in the narrative flow. In my game, I kept the encounter available (though no one opted to stick their head through the door) but I "nerfed" the damage - I would roll 1d8 + 1d3 (for falling). Outright death is now unlikely (though not impossible - it's a 4% chance), but a major wound is going to happen about 65% of the time. Good enough to punish a foolish Investigator and set the tone for the Scenario, but not so disruptive. 

Fighting a Zombie: Moderate Lethality; Low against well-prepared Investigators
Realistically, the Investigators may face 2 or 3 zombies of any real threat during the climactic ritual. These zombies don't have a very high skill, so a hit is not super-likely, and when they hit they do between 2 or 3 HP (on the low end, for Zombie Maggie), and an average of 7 HP (for Zombie Bear) per round.

Assessment: They should be taken seriously, but if there is an Investigator on watch with a decently powerful firearm - and if the Investigators know their business, there will be - there's no reason these zombies should spell death for our PCs. They make a good threat and tension-builder, and are placed correctly in the climax of the scenario.

Being Attacked by the Lurker At the Climax: High Lethality
When freed to roam, or if an Investigator encounters it outside the warded area, the Lurker does 1d8 + 1d6 damage each time it hits, as in the trapdoor example above.

Assessment: The Investigators have to do something foolish to wind up facing this thing directly - go outside, or break the pentagram, or let the zombies tear the wards off the windows - and frankly, once you hit the climax, any such foolishness can certainly be punished with lethal force.

SAN Loss - Easy to calculate, but the effects are hard to predict

When Investigators experience something that goes beyond what their mind and worldview can handle, their sanity takes a beating. When they have a bout of temporary, or even indefinite, insanity, this can have two effects:

• Throw a big bunch of chaos into the scene, with the now-insane Investigator doing dangerous things to himself or his companions
• Take that Investigator out of action for the remainder of the scenario (or forever), similar to a death. 

There are a couple of opportunities to lose significant chunks of sanity in this scenario. We can do some quick math to see, on average, what we're dealing with:

• Each of up to 3 Zombies cause 1/1d6 SAN loss to see
• On average, each one will cause ~2-3 SAN loss, so this is (on average) 6-9 in one game-day if you use all 3 zombies during the scenario; if things go very wrong, you could be looking at 10-18.
• The Lurker causes 1/1d8 SAN loss to see (in various ways, not each time)
• On average, this will cause ~4 SAN loss in one game-day
• Finding Maggie's corpse causes 1/1d4, or ~ 2 SAN loss in a game-day
• Witnessing the horrible death of an Investigator at the hands of the Lurker causes 1/1d6 SAN loss, so about ~3 SAN in a game-day. When combined with the 1d8 for seeing the Lurker, this can contribute to a potential TPK situation (see below, "Complications"). 
• Assorted other nickel-and-dime SAN losses, like reading Merriweather's journal, can take off 1d2 or 1d3 SAN here and there.

So if we focus on just the ritual itself, Investigators who roll poorly can easily lose 10+ SAN in a game day. What happens then? If the Investigators are relatively fresh and have high starting Sanity, they are unlikely to be indefinitely insane. However, a temporary bout of madness (with a phobia or mania) results from losing 5 or more SAN in one roll - and this is quite possible.

If an Investigator loses 20% or more of their total remaining SAN in one game day, they will go indefinitely insane - this is akin to death, for our purposes. For the Investigators at my table, this could well be an issue - their SAN levels range from 41 to 69. If they were to roll poorly and lose 10+ SAN points, we could be looking at 1 or 2 indefinitely insane Investigators. 

So - what do I do about that? I think I'd leave it as-is, but I would keep an eye on cumulative SAN loss within each game day. If it's starting to creep up, especially for the lower-SAN Investigators, I might ask them if they want to "call it a day" and return rested the next day. I could either do this out-of-character, or I could do it within the narrative, by describing the increasing effects of the mental trauma they've sustained, and describing a growing urge to rest and retreat. 

Then, if they decide to press on anyway, they've made an informed choice. Any indefinite insanity, then, is on their heads.

Complications: Mixing SAN loss and HP Loss

The above examples treat each encounter as a discrete event: you fight Red Jake, then you fight some zombies, then you (maybe) fight a Lurker. Or - you discover a mutilated corpse, then you see the  Lurker out of the corner of your eye, then you see Zombie Jake, then you see the Lurker's true form.

In practice, though, the Scenario gets messy. If an Investigator happens to see the Lurker's true form during the ritual, then goes mad and starts blasting his friends with his .45 due to acute paranoia (this actually happened in an actual play I listened to), that introduces a level of lethality we didn't account for. 

There's no easy way to calculate these interactions, but it's important to be aware of. As a Keeper, you should be ready and willing to throw a symphony of terrifying stuff at your players - but keep one foot on the brake and the other on the gas, so you can keep the experience within the general bandwidth you're aiming for. 

If an insane Investigator starts firing at his comrades, she is doing some of your lethality work for you! You can feel free to quietly ditch the Zombie Bear you had waiting in the wings.

Conversely, if those pesky Investigators are holding it together pretty well and passing all their SAN rolls, it might be time to step on the gas and let them feast their eyes on a cadre of walking corpses.

SO! Do you struggle with knowing when and how to kill? What have you found works really well for you? Share your stories and tips in the comments, if you would?

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Next Post: An After-Action report on the first half of Edge of Darkness (for real this time!)

Want more of what I do? I have a number of best-selling Adventures and GM guides for the 7th Sea system available via DriveThruRPG! They are reasonably popular and shockingly inexpensive, so check them out!

I'll soon be working on writing my first-ever CoC scenario for publication, giving it the same "behind-the-scenes development" treatment you've seen so far - so watch this space for future posts on that topic!

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MATH-Y PORTIONS TO FOLLOW, IF YOU'RE INTERESTED
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Without doing a full analysis of every possible situation in which an Investigator rolls when death is on the line, we can pick a few representative cases and get an idea of how hard a Keeper has to work to kill an Investigator - or, conversely, how easy it is for an Investigator to off themselves or descend into madness.

Here we go. Combat death is a more complicated discussion than Sanity.

Hit Points, Injury, and Death

Investigators need Hit Points (HP) to live. These are derived by adding Size and Constitution and dividing by 10 (round down). The average Investigator, let's say, has a total SIZ+CON of around 110, and so starts a game with 11 HP (on average, assuming they aren't nursing any horrible injuries from a previous game session).

There are a lot of ways to lose HPs in this game, but ultimately the results are funneled into one of [X] effects:

• Regular injury - just deduct some HPs, and fret a little bit
• Lose half or more of their max HPs in one shot- major wound, make CON roll
• If failed, fall unconscious
• If char with major wound hits 0 HPs, they are dying
• Make successful CON roll at end of reach round, or die
• If they get to 0 HP without a major wound (like after a bunch of minor wounds), they don't die, just fall unconscious

Assuming they live, a wounded character needs days to weeks to heal back to where they started.

So how might an Investigator get injured? Let's look at a couple of examples of weapons, both man-made and beastly. Keep in mind an Investigator with a max HP of 11 would need to take 6 or more damage in one shot to receive a major wound.

Human Weapons

• Getting punched by a mook: 1d3 + damage bonus (usually none, but can be 1d4 or 1d6 for truly large people)
• Average damage is 2 HP per combat round (w/o bonus); max is 9 (w/ 1d6 bonus).
• The Investigator could survive 6 rounds of combat (w/o) bonus on average if they take an unanswered hit each round (in practice, the Investigator will probably dodge or fight back some rounds, so it's likely to be less lethal than this)
• Can only take a major wound from an opponent with damage bonus. 
• With a 1d4 or 1d6 damage bonus, the chance of rolling a major wound is about 1 in 5. The odds of the attacker scoring a major wound in the first 6 rounds of combat are roughly 74%. 
• So: against a regular-sized mook, a pretty boring fight. Against a big thug, a real likelihood of major wounds and death.

• Stabbed with a small knife: 1d4 + damage bonus
• Very similar to punching; an 11-HP Investigator can expect to go 5-6 rounds of combat, at least, before falling unconscious. A major wound is a concern (~20-25% chance), but not top of mind.
• Knives and other blades can also impale, so somewhat rarely the attacker will roll well enough to do this. In that case, the minimum damage done by a small knife 4 + 1d4 + damage bonus, which makes a major wound - and thus death - a very real possibility.
• Hit with a baseball bat: 1d8 + damage bonus
• Even without a damage bonus, more than a third of the time this is going to cause a major wound right off the bat (pun intended). A one-hit knock-out, or unconsciousness in 2 rounds, is a real concern for the 11-HP Investigator.
• Handgun: 1d10 (impaling with extreme success for 10 + 1d10)
• Major wound 40% of the time for the 11-HP Investigator; unconsciousness likely in 2-3 rounds.
• Impaling means just about instant death, or close enough.
• Shotgun at close range: 4d6 - goodbye, face.  (Average is 14 HP lost per hit).

Beast/Monster Weapons

Animals, ghouls, creepy-crawlies, Mythos monsters - they all have a variety of ways to inflict physical harm. Many of them ALSO have ways to inflict harm on sanity and other awful things, but I'm going to skip over them for now. So in the simple case, let's just say you're fighting a...:

• Byakhee: 1d6 + dmg bonus (1d6) - average 6 HP per round, but it can attack twice, and it can also latch onto you and drink your blood and kill you that way...
• Dark Young: speaking generally, 4d6 per turn like a close range shotgun, but in practice much nastier...
• Deep One Hybrid (not using a weapon): hits like a human! Hey, that's good news! Then again, they can also hit you with a particularly gnarly spell...
• Shoggoths: 8d6, plus an assortment of other nastiness, and they can hit multiple Investigators at once or engulf them and tear them apart in a nightmare of squishy gelatinous awfulness with the tearing and the rupturing and the... you know what? Don't fight a shoggoth.

Combat death summary: Any enemy more menacing than a medium-sized fistfighter is going to present an increasingly serious threat of major wounds and death if the Investigators just stand straight and slug it out. In practice, combats may be more or less lethal depending on what tactics the Investigators use, and how everyone rolls.

As a Keeper, you can regulate the lethality of your encounters to some extent, but it seems better to do it by adjusting the situation (type of enemy, which attacks they'll use, what kind of cover or escape options the Investigators have) rather than fiddling with the damage numbers.

Indefinite Insanity

Sanity Points (SAN) start out equal to Power (POW). Savvy Players often prioritize things like Power and Intelligence over size, so let's say the average POW is up around 70, and thus the average starting SAN is around 70 as well. Again - this is a broadly applicable average, not a precise estimate.

Losing Sanity

- Basic SAN roll: lose X/YdZ

• 5 or more SAN points from a single roll:
• Major emotional trauma - make an INT check
• If succeeds, (likely will succeed slightly more often than not), temporary insanity (1d10 hours); can add phobia/mania, or corrupt a backstory, or have delusions
• If fails, remain sane for now
• Bout of madness, for a certain number of rounds
• Lost 20% or more of your total sanity in one game day, indefinite insanity (weeks, months, forever). I'm not sure if you have to roll for this or if it's automatic.
• So for a fresh-faced investigator with 70 SAN, this is 14 SAN points in a day. That's hard to do - you'd have to fail several mild SAN rolls, or two big ones. But as your Investigator presses on, and max SAN falls due to the mythos, or you don't recover it all between days... the likelihood goes up. 
• When you get to about 50 SAN, the odds of indefinite insanity in any one scenario are comparatively high. When you get to 40 or 30, you start to worry about going 'round the bend in one bad roll.

[Well-constructed scenario will tend to place the riskiest rolls - highest SAN loss, highest HP loss - towards the climax, or at least at a peak in the narrative tension.]