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The Cthulhu Hack

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What's The Cthulhu Hack?

It's a standalone game of investigation horror, pitting ordinary people against the sanity-shattering horrors of Lovecraftian gods and monsters.

It's a fast and simple system, with just two mechanics - Saves and Resources - that handle your ability to escape threats and to manage your dwindling faculties for investigation and sanity.

Why Choose The Cthulhu Hack?

Role-playing offers a lot of games set against a backdrop of Lovecraft's mythos; The Cthulhu Hack focuses on simple, accessible rules and mechanics designed to emulate the slow spiral of self-destruction that dominates Lovecraft's original tales. Campaigns become about the over-arching threat against the whole of humankind, rather than the insignificant lives of just a few investigators.

What's in the Core Book?

Revised and expanded since the original 2016 release, the 52-page core book offers:

  • simple mechanics to handle threats and investigation, using a standard set of seven polyhedral dice (from 1D4 to 1D20)
  • ready-to-play archetypes for quick pick-up play or a fast and flexible character creation system to tailor Investigators to your specific needs
  • a range of tweaks to the core mechanics, both standard and optional, to tailor the game to your style - including Wealth, Fortune, Adrenalin and Shock
  • a shambling horde of Mythos horrors - including Mi-Go, Deep Ones, Shoggoth and more - to challenge your Investigators
  • a complete and updated adventure - Save Innsmouth - as well as a 2-page example of play

Want More?

If you want to learn more about the game itself, check out an example of adventure conversion of The Haunting and the rough-and-ready conversion guide for other popular Mythos games on the Just Crunch Games website [external link, use the Search to find a ton of articles], or give the game a test run with the Quickstart Nocturnal Rites.

After that, you can create new horrors using the tools in From Unformed Realms, delve into creating your own investigations using the ENnie nominated The Haunter of the Dark, disturb the spawning sack of the cult of Shub-niggurath in The Dark Brood, or dive right into a bunch of ready-to-run investigations in the award-winning Three Faces of the Wendigo and Thro' Centuries Fixed.

Reviews from Other Sites

Paul Maclean - "The Cthulhu Hack… at The Breakfast Club, we love it!" (Cthulhu Breakfast Club /, at AireCon 4)

Steven Robert - "If you want at least a little bit of butt-kicking, or if you like tossing dice, The Cthulhu Hack is the clear choice." (RPGGeek)

Eric Dodd - "I welcome the appearance of The Cthulhu Hack to the crowded Lovecraftian RPG mantlepiece. If you liked the simplicity of Cthulhu Dark but felt you needed a few more tools and levers to build a game around, without having to track 40 or 50 skills or detailed weapon statistics, then The Cthulhu Hack might be just what you’re looking for." (RPGGeek)

Mike Hill - "The bottom line is that I will actually play this game. I download a lot of projects that never make it off the hard drive." (The World According to CARP)

Simon Burley - "The Cthulhu Hack hit my doorstep today and it's bloody good!" (author of superheroes classic Golden Heroes)


  • Created with The Black Hack: This is a standalone product, including the Open Game License material of The Black Hack.
  • The core rule book file is digest-sized, scaled to A5. Save Innsmouth was previously available as a standalone product.
  • Buying the softcover provides the PDF copy of the game for FREE.
 Customers Who Bought this Title also Purchased
Reviews (5)
Discussions (9)
Customer avatar
Paolo M February 28, 2023 10:22 am UTC
I found another typo or formatting problem - page 12:

*Withering Words.* You can use CHA
for attacks (instead of STR or DEX),
providing your opponent can hear and
understand you. Roll damage as if
Armed; if reduced to 0hp (or no Hit

There is nothing shown after "Hit"... so I do not know what the effect of a "Withering Words" attack will be.
Customer avatar
Paul B February 28, 2023 10:38 am UTC
All archetype Abilities are listed in the Special Abilities under the Freeform Characters section. Withering Words appears, complete, at the bottom of the list on page 16.
Customer avatar
Jeremy H December 15, 2021 2:48 am UTC
Hello. Would you guys help me boost my current Kickstarter? I'm putting together a third volume of monsters for Black Hack. I have two other volumes here on DriveThru. it's been a few years since I published those and hope to get some additional exposure via other Black Hackers. Thanks! :^)
Customer avatar
Robert N July 05, 2020 9:08 pm UTC
So I just downloaded this and I love the simplicity of it. It makes for a fast and fun game (or so it seems, I have not run a game yet). I do have one question about resource rolls. The rules talk about Supplies, but there is no spot for a Supplies die on the character sheet. Am I missing something? Any help would be appreciated.
Customer avatar
Paul B July 12, 2020 6:18 pm UTC
A Supply Die is a Resource (page 4) and is connected with the longevity of a piece of equipment, in terms of power, repair, reliability, or amount of ammunition. However, you should only assign a Supply Die if it's important.

-- You would assign a Supply Die to water if being thirsty was going to hurt - so, an investigation in the desert definitely needs an SD for Water.
-- If you're in World War trenches struggling through dirt and barb wire, an SD for Bandages is important to patch up wounds and keep them clean.
-- In a modern-day investigation in downtown New York, neither bandages nor water matter enough to be monitored moment-by-moment, so you wouldn't give them a Supply Die.

Essentially, Supplies are transient — they last as long as the Supply Die remains, and when you roll 1 or 2 on a D4, they're gone. Bullets, Flares, Water, Battery Life. That means on the standard character sheet they end up being something you write on and erase when you're done.

I'm...See more
Customer avatar
Gordon R October 10, 2019 12:18 pm UTC
Page 12, last paragraph..."if reduced to 0hp (or no Hit" - the end has been cut off. Any chance you can let us know what the sentence should say? Or is there a downloadable errata somewhere? Thanks.
Customer avatar
Paul B October 17, 2019 8:05 am UTC
Hi Gordon. The missing bit is word-for-word the Withering Words Special Ability on page 16. I will check the pagination on the PDF and upload a new version when I next have the opportunity.
Customer avatar
Antonio M February 03, 2019 3:49 pm UTC
Is there a mechanic to use The Cthulhu Hack to play in modern times? Or is based in the 1920s like CoC?
Customer avatar
Paul B February 03, 2019 5:59 pm UTC
There's nothing within the structure or mechanics of The Cthulhu Hack that ties it to a specific time period.

Of the adventures released so far: Save Innsmouth (2010s), The Haunter of the Dark (1930s), Thro' Centuries Fixed (present day), Three Faces of the Wendigo (three time periods over 200 years), The Dark Brood (present day) --- and the next four adventures are mid-1950s, two in present day (Mother's Love) and late 22nd century (Valkyrie-9).

I hope that that's helpful!
Customer avatar
Antonio M February 04, 2019 12:00 pm UTC
Thank you so much!
Customer avatar
Nathan C February 20, 2018 5:45 am UTC
Sorry to bother you, is the POD version coming back anytime soon or am I just missing it?
Customer avatar
Paul B February 20, 2018 6:44 am UTC
No bother at all! I haven't overcome the hurdles of making a POD version available here, because the process keeps running into errors that I'm having trouble resolving through the pre-print stage. However, you can get a fine print edition from All Rolled Up's web store (with matt cover and off-white pages) or Lulu (with gloss cover and white pages). The moment I can get the issues resolved, there'll be POD here, too.
Customer avatar
Paul B July 08, 2018 1:38 pm UTC
Files have been submitted - including all the latest updates to content and the revised cover image. Fingers crossed!
Customer avatar
Paul B July 31, 2018 4:49 pm UTC
Softcover option now available to order! Latest version of the Core Rules with the latest version of the cover.
Customer avatar
J. W November 25, 2017 3:48 pm UTC
Seems the new HD as Resource (HDR) document isn't quite complete. One of the usage examples is truncated that starts with "A robust investigator" ... ends with "reducing the attack to 9 damage, which means the player" ... which means the player what ? Figure it would have been nice to also have the details on healing when running HDR. I get that the character can heal 1HD daily by themself ... which would be a step up ... but what if they receive external healing, one step up ( limited at HD max ) per HD of the heal ? I'm looking at using HDR generally, I love that this removes yet another distinct mechanic from the game and makes things just that much more consistent.
Customer avatar
Paul B November 25, 2017 5:26 pm UTC
Thanks for the catch - I have amended the section boundary to show the bit that was missing and added a bit of an experimental note about healing, which I leave to individual groups to tweak to taste.
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