Quick Conversion for Cthulhu Hack

If you have an adventure from any system that isn’t Cthulhu Hack and want to convert it, it really couldn’t be simpler. First, read the adventure cover to cover. Once you’ve done that, keep the element below in mind. If you don’t have the time, read it and keep the following in mind, but expect it to be rough and ready.

Assessing Threats and Clues

At a basic level, when you read an adventure for another Cthulhu system:

• If you identify a conflict, hazard, or obstacle, it’s a Threat handled with a Save.
• If you identify a clue, work out if it’s essential or peripheral.
  • If essential, make it available to the investigators when they reach its location through the most reasonable channels (considering their occupation, skills, abilities, or requested activity).
  • If peripheral (i.e., additional information, colour, background) and will not block progress if not found, then you need the Players to seek it actively. Occupation, skill, abilities, etc., might be helpful, but peripheral clues warrant a Player stating an intent to look, research, etc.

Handling Resources

Whether essential or peripheral, once a clue is found, the players will be asked to make a Resource check (Flashlights/Smokes/Sanity) depending on the nature and approach to discovery.

• If they roll 3 or more, they can move on.
• If they roll 1 or 2, it’s essential to take a moment to consider what aspect of the clue uncovered connects the dots with their background and unsettles them. This can be sufficient for the Resource to break and drop to the next lower die, highlighting the potential impact of their decisions on their characters.

Drilling Down into Clues

In Call of Cthulhu, Trail of Cthulhu, and other games (even simple ones like Cthulhu Dark), the text of the adventure will usually call out what skill a character requires to find a piece of information. For your group, that way to discovery is not essential, so much as how that discovery links to them and joins the dots of their dark revelations.

You can use an identified skill as a way to target a likely discoverer (i.e., if you need Language (Sumerian) in the text of an adventure, you might lean toward an Adventurer or Scholar discovering it over a Bruiser or a Ruffian, but, that said, it’s not impossible!).

Conversion should be loose but coherent. Cthulhu Hack is less about the specifics of what you know or don’t know, but there should still be a shred of sense. A Bruiser might understand a few words of Sumerian, but then I suggest you explore that — why do they have that particular skill? A family member with an interest in ancient texts? A teacher at school who saw potential where others didn’t? A chance encounter with a lover, a stranger, or a guide on a journey? And if they roll a 1 or 2, what did these connections hide, obscure, act out, or accidentally reveal that left the character unsettled?

Rough Conversions

For things like hit points and combat, compare and improvise. A system with hit points that run in the 10 – 20 range for humans, half them. Eight to twelve, keep them as is. It is often helpful to find an average weapon and see how much damage it causes. An average CH2e character might do 4 – 6 damage with a handgun — compare that to the system you’re converting and then adjust all other weapons. So, in a system where a handgun does 2 damage, double it. Ten damage? Half it.

You can read more in a much earlier post on Rough Conversions, but it’s probably overkill to fret over the details of transforming a character from one system to another. If an ally knows a skill, consider it a Step Up (where they know a little) or an Advantage (where they know a lot). If an enemy or competitor knows a skill, consider their expertise a Step Down (if they know a little and work against you) or a Disadvantage (where they know a lot).