Running Cosmic Horror in D&D

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Do you guys have advice for portraying cosmic horror in D&D specifically? I know it isn’t the best game for horror, but it’s all my RPG group is willing to play.


Hey there, thanks for writing in!

As you’ve already guessed, D&D is not a great system for portraying cosmic horror, or any kind of horror really. Horror depends a lot on disempowerment, and D&D characters are incredibly empowered, especially in more recent editions.

However, it sounds like D&D is your only option, so let’s see what we can do. First of all, there are d20 horror games out there, and your group might be willing to try those since they are still within the D&D bubble. D20 Call of Cthulhu is the obvious option. I’ve never played it, but I suspect it would be better than straight D&D. Ravenloft is another option. It’s more geared for gothic horror than cosmic horror, but that’s still more horror than you’ll get from a standard 3.5 or 5E setting.

Outside of systems specifically made for horror, there are a few things you can do to make your D&D game better suited to cosmic spookiness.

  • If possible, use an older edition of D&D. 5E and 4E are both much farther into the magical empowerment circle than 3.5, AD&D, or Basic. In the newer editions, even the non-casters have what feel like magical abilities, which is fine for high-fantasy adventure but not great for horror.
  • Keep the PCs low level. Cosmic horror is all about feeling like ants in the hands of giants. The higher level a PC is, the more in control they’ll feel and the less the horror will bother them.
    • You might even try one of the d20 mods that starts the PCs as 0th level commoners. Cosmic horror is also strengthened by playing normal people rather than badass adventurers.
    • Eventually the players will still expect to level up and the horror will fade, but it’ll be there for the beginning.
  • Keep magic out of the PC’s hands. In cosmic horror, the supernatural needs to be mysterious and dangerous. Having a party member who can conjure fireballs or call down miracles will make the magic much more familiar, so stick with martial classes.
    • Alternatively, you could house rule a system to make D&D magic more like Cthulhu magic, where using it has a serious cost to the wizard’s physical or mental well-being. This would be more work, especially since casting classes would need to be re-balanced, but it would allow for magic without breaking the cosmic-horror theme.
  • If you’re up to it, you can house rule a mental-health system to represent the damage done by encountering the strange and horrific. 5E has a “Madness table” in the DMG but I don’t recommend it, both because it’s clearly tacked on, and because associating mental illness with cosmic horror can be problematic. You’d want something more complete.
    • To keep things simple, this system could be “stress points” (I advise against “sanity” since it has ableist implications) that work the same way as hit points, except in response to mental trauma rather than physical trauma. They’d probably be based off a character’s wisdom stat.
    • It’s good if the PCs don’t have an abundance of either stress points or hit points, since it needs to feel like they’re at serious risk, which is another reason to keep the game low level.
  • Some monsters work better for cosmic horror than others. The mind flayer is always a good standby, but you can also use weird beasts like beholders, blink dogs, aboleths, and basically anything that seems weird rather than just big and threatening.
  • Now for some general cosmic horror advice:
    • It’s best to craft scenarios where the PCs have to do something other than defeat the monster in personal combat. Maybe they need to find the spell that closes an inter-dimensional gate, or evacuate a village before the Great Old Ones swallow it. Defeating the monster in combat reduces the horror, whereas escaping by the skin of the PCs teeth can actually increase the fear.
    • Don’t fully describe the supernatural elements unless you have to. Instead, the PCs can find the aftermath of a monster’s attack, see a glimpse of something in the shadows, or have the effects of a spell hinted at by a cackling cultist.
    • Emphasize the inhuman nature of the supernatural. The Old Ones might not even care about killing humans. Maybe they just dislike the heat, and so they’re bringing about a great chill that kills humans as a side effect.
  • Finally, you can always work on tricking your group into trying something outside of D&D. I recommend Torchbearer, though Dungeon World is another option, as a gateway system, since it’s specifically designed to recreate the feeling of first playing D&D. You could pitch it as a D&D tribute game, and only later will they discover they’re playing a story-focused game.

I hope some of that is helpful. You’ve got your work cut out for you, but a determined GM can overcome most obstacles.

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  1. American Charioteer

    It could work to your advantage that they are only used to DND; because they are so used to having so much power in the setting it will be more impactful when you take that power away. DND players are especially used to being able to restore full hit points after every encounter, or at least every day. If something is preventing them from healing and they don’t know what it is, that will both create an atmosphere of suspense and raise the stakes, since now every wound pushes them a little closer towards death.

  2. Michael Campbell

    Unearthed Arcana in 3.5 had a Cthulhu-like magic system.

    A lot of low level stuff can seem like horror. A shadow is pretty much unstoppable without magic weapons.

    I however would be asking the question “why do the players refuse to play other game systems?”
    I’ld say to you; look for a game system that is a different system but still has the feel of high adventure `n’ B-grade serial style “puttin’ the kybosh on the bad-guy”. E.g.
    And then later ask the players to play a game with more eldritch horror, after your players have become familiar with the fact that you-Game-Master-out-of-your-imagination and not merely out-of-the-rule-book. They’ll then be comfortable with the fact that whatever system is chosen, the GM can make or break your character at will, regardless of system.

    So talk to your players and find out what’s going on.

  3. Jenn

    The great thing about monsters from the far realm is that they don’t have to follow the same rules of magic everything else does, so fun could be had there. Especially when the high level caster’s magic spell interacts with the critter in weird and wonderful ways. Also as one of my GMs knows well, if you give the party a useful, powerful but obviously evil artefact, one of them will still use it.

  4. greg

    Ability Damage/Drain is a good mechanic to bring out in a horror game. Almost all of them can simulate a diminished capacity due to exposure to eldritch horrors. And even a fighter with hitpoints in the triple digits gets a little shaky when he takes a 1d6 from his Charisma score of 11.

  5. Athien Dickens

    Curse of Strad would be interesting, being hunted by a killer.
    Read horror stories.
    Good intense music
    Build suspense in the story
    Get a horror campaign and re flavor it for cosmic.

  6. NewtypeJ

    Ableist? I’ve never heard of anyone mentioning that. Insanity from seeing Cthulhu is different from having a mental disability. Just saying, I highly doubt Lovecraft cared about mental illness, I mean the dude was a racist for crying out loud.

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