A downloadable game

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Building upon the groundwork set out in Cthulhu Dark by Graham Walmsley, Cthulhu Deep Green contains a modified rules set for playing as Agents of The Conspiracy: a shadowy government agency tasked with concealing evidence of the supernatural.

This 42 page PDF contains all the basic rules you’ll need to play,  Handler’s advice for running your own scenarios, and tables to help inspire play. Playable with three to six players with sessions lasting two to four hours.

Also included: Food of the Gods, a fully realized scenario set in the Seattle underground dining scene. 

With a focus on quick setup and improvisational campaign play, the rules of Cthulhu Deep Green are designed to focus the human element while keeping the action tense and dramatic.

What will your agent give up to protect the public from terrors beyond sense or reason?

Pick up your phone and report in.

Author's Notes: 

This material has a general content warning for depictions and allusions to violence and psychological manipulation.

Feel free to download the rules preview before purchase.

Unlike similar games, CDG steps away from references to sanity and insanity but it does deal with stress related disfunction and issues of work-life balance.

I reserve the right to update these files periodically with new material.  Follow this account for updates.

Unofficial CDG Soundtrack


Buy Now$7.00 USD or more

In order to download this game you must purchase it at or above the minimum price of $7 USD. You will get access to the following files:

Food of the Gods.pdf 25 MB
CDG PDF.pdf 39 MB
CDG Spread.pdf 39 MB

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Download demo

CDG - Rules Preview.pdf 16 MB

Development log


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Q) What in-game effects do Injuries and Debilities apply? Justify a Failure Die?

They might, though remember a player needn’t justify a failure due beyond the idea that it makes a roll more interesting.

Primarily they put a limit on how much violence an Agent can participate in. Each slot can only hold a single injury and a level three injury takes you out of the action without immediate treatment so they act to encourage players to seek more clever or non-violent ends to an operation. If you’re The Handler, don’t be afraid to threaten players with very serious injuries if they partake in violence.

As for the flashbacks: I’ve found them to be much more interesting in Playtest than the previous resource mechanic. They allow players to explore how they feel about horrific events on a personal level and flesh out their characters before they die horrible deaths, which makes the bad things that happen to them all that much more awful.

(and thanks for the typo, I’m currently editing this doc a bit to get ready for a potential print on demand version so I’m actively doing editing and revision of the docs over this next week!)

The process of marking Anchors is not in the latest version of these rules. Can you please update?

(1 edit)

The rule has been changed! It's a brief rule now, but an improved one:

PG. 14, At Home Scenes

"At home scenes are activated in one of two ways:

Once, after a mission.

Or when Agents mark an Anchor."

In a future revision I'll consider making a reference to this rule in the anchor section!

PS: I added a clarification to the character creation section under “Anchors.”

AFAIK it doesn't explain the purpose of marking an anchor (previous version stated it's to prevent Stress/Insight increasing)?

Correct on the previous version. It should now say 1. That you can activate an At Home scene by marking an Anchor in two places:

Right - I get it now! I think my awareness of the previous rules meant I was laboring under a mis-understanding.

"Anchors may be marked to falashback and activate an At Home scene at any time."

(Spotted a typo above, btw!)

I should have read fintcher's thread below more closely - apologies for my obtuseness.

From your playtesting, how did the flashbacks go in terms of potentially disrupting the flow of the horror? Like, you're at some climax to the story, and a PC who has a high stress marks an anchor and triggers a flashback to wandering fields of flowers with his girlfriend? Jarring or not?

Love the game. In particular the cover and exposure track.

Question: can destroy the unnatural treat reduce the insight? Like roll a D6 and if it's lower than your current value you reduce insight by one. Cthulhu Dark has a similar mechanics to "repress knowledge"

Thank you so much!

To answer your question: No, Insight is permanent and acts as a sort of marker for how far gone your Agent is. In general, depending on the operation, Agents should face a lot fewer Insight checks than Stress checks, though.

That said, if you prefer Cthulhu Darks suppression rules there’s no reason you couldn’t tack them on for Insight checks and I do have plans for some more optional rules along these lines in a future supplement.

Oh no I like it, also because you have removed the insight on 6, and now you have the stress for "normal" situation, just curious if you were planning "sanity" rewards for doing a good job (either reduce Insight, or the stress or Unmark an Anchor)

The other question was about the home scene: you can activate one in play by crossing an Anchor, so I guess the only one that makes sense is "Engage in Self Care", since the others don't involve your Anchor (and the stay on the case one is something you are already doing while playing). Besides that I love it: adding a clock for exposure is genius, we were thinking to do something similar playing CoC and DG to "dump" the failure in rolls that succeed no matter what (like forcing a door, you will succeed but someone will see you)

Crossing an Anchor allows you to play out any of the At Home Scenes (though repairing an anchor would be a bit recursive) so long as you include them in some way!

Presumedly they are a big part of your Agents life, so bringing them up in therapy, having them visit you in the hospital, or being an important part of your self care are all pretty likely.