OGL Cthulhu Material (esp. Monsters & Spells)


For past several months, some friends and me have been trying to compile a fully "open" ruleset that could be used for playing Cthulhu investigative roleplaying games with a similar style to "old school" editions of the most popular Lovecraftian RPGs.

So far we have been very lucky in having several OGL-based rulesets to draw from -- most notably the Delta Green RPG ruleset (aka "Misery Engine") and a number of open d100 rulesets like Renaissance. This has allowed us to piece together most of the skeleton of a purely "open" Lovecraft RPG -- investigator creation, skills, combat, sanity, tomes, spell mechanics.

What has been less easy is finding good OGL sources for creature/god statistics, and also a grimoire of "Lovecraftian" spells. Most games have these things, but exclude them trom the OGL content.

Does anybody here on YSDC know of any other sources we could consider for getting open content which covers those two missing areas? I guess we could issue an "Open Cthulhu SRD" which has none of these things -- just rules -- but I'd prefer to have something of Lovecraft's gods and monsters weaved into the free ruleset we release.

Thank you in advance for help or assistanses,

Chris Rosen


Master of Mutant Design
Validated User
Realms of Crawling Chaos from Goblinoid Games. It adds Lovecraft to more typical fantasy settings but it does include a fair number of creatures and a few science fantasy items and spells. And the text of the book is open content.

It does not have Sanity. In place is something I like more- psionic powers that allow the creatures to use their brains rather than their presence to twist the minds of their foes. Cthulhu can even strip away a personality and replace it with something more useful for a few weeks via RCC's version of id insinuation.

I have no idea if any of it is open content, but another possible source is Silent Legions by Sine Nomine. That is more of what you are looking for, but it may have no OGC at all. Forget this, it isn't under the OGL.
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Registered User
Validated User
Lovecraft is a sticky one, due to several of his works being right on the line between public domain and rules that kept extending copyright protections over the years. This article, while not definitive, might shed some light into the issue: https://lovecraft.fandom.com/wiki/Copyright_status_of_works_by_H._P._Lovecraft. Don't assume that because someone else used or redefined some of these monsters in a set of rules that may be freely available this gives you any kind of right to reproduce them elsewhere. Check with a copyright attorney first, or at the very least find clear answers that point you in the direction of being able to use the material freely.
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