Cosmic Horror in D&D
I’m going to go against the grain here in relation to the typical advice I see about cosmic and existential horror in D&D 5e. Feel free to disagree with me and I understand the advice here is not universal. It depends greatly on the group’s willingness to indulge in the horror and lack of power.
The first campaign I ran that I truly loved, that made me experience that sense of childlike wonder and excitement that makes GMing worthwhile, was a cosmic horror game. And as such, I do believe there’s a way to make cosmic horror work. It isn’t the greatest system for it, but if you want that genre mixed with medieval fantasy, there are certainly worse options.
So how do you make it work? Here is my advice:
Set expectations
Not everyone is going to head into a D&D game wanting to feel powerless and dread the journey ahead. D&D at its core is about adventuring and heroics. Cosmic Horror is the opposite.
So, before the game starts, before even session 0, let your players know what’s up. Let them know that it isn’t a typical game. Let them know that they’re gonna struggle, that winning might not be an option, and that fleeing is valid. If they agree, great. But in my opinion, it shouldn’t be a passive agreement. I’d look for an active interest, one that shows that they’d help play into it.
Your players going along with the dread is vital to making this work. They have to accept the premise and not fight against it — out of character at least. That will make everyone’s life so much easier.
Flexibility
Your vision will not be executed in its entirety. That is the case of many tabletop games as a whole, but it rings true for cosmic horror games especially. This is because the nature of cosmic horror is to be unpredictable and undigestable. When there’s something greater than you, something which is a higher class of being, it cannot make sense to you.
This once more applies to all types of games, but don’t get stuck on old ideas that you had planned, if you come up with something better, more dramatic, or intriguing, go with that. Your game will be better for it, especially when horror games are all about dramatic events and intrigue.
Environmental Storytelling
I will spare you the nonkey details, but there were some weird things happening in my town. There were odd customs. Everyone was overly friendly, the north wall of every building had to be painted red, and all the art was grotesque and distorted.
From a lore perspective, this cosmic entity that controlled the town communicated with the constituents, but in a way they could barely interpret, leading to odd, unusual customs and behaviors — as directed by the entity.
In my opinion, it is best to lead clues to the strange happenings and leave them open to interpretation. I didn’t have any NPC know about the entity, most of them blind to the oddities. But there were some who knew things were off and changing.
I also had many dungeons and adventuring sites filled with logs, journals, and other expository items. These all gave the perspective of people who weren’t blind.
This worked really well for me. It gave clues that led to bigger yet unclear ideas. It let the story speak for itself in a way and let people know what they wanted to know. It was cryptic enough to inspire interest and didn’t have an NPC forcing information down someone’s throat.
Conclusion
My game was not a masterpiece. It had many faults, but some of my favorite moments as a DM. When your players know they’re outmatched and have to think, it can lead to some great roleplaying.
Cosmic horror can work even if it isn’t the best fit. But it doesn’t have to be. I wouldn’t recommend trying to recreate Call of Cthulhu in D&D, but still using the core elements of Dungeons & Dragons and just adding a genre on top can be a lot of fun. Which is what my game was: fun. That’s all it needed to be.
So figure out what works for you. Follow this advice or discredit it. It might not be right for you. Either way, if it interests you, at least give it a shot. Ask your players and see how it goes.
You don’t need something to be amazing for it to be worth attempting. It doesn’t even need to work.