GTM #224 - Bringing Lovecraft to Life
by Sandy Petersen



Petersen Games is releasing its first RPG product! 

It's a new project titled Sandy Petersen’s Cthulhu Mythos – Pathfinder has over +100 Cthulhu entities, as well as rules for bringing Lovecraft (from the foremost experts of it) to the High Fantasy/Sword and Sorcery world of Pathfinder.

Lovecraftian horror, however, is famously difficult to adapt to non-literary sources, including film and tabletop RPGs. 

But most challenging of all is bringing his monsters to life visually. In producing a Cthulhu Mythos themed sourcebook for a roleplaying game far more focused on tactical combat than my own RPG (Call of Cthulhu), we had to figure out how to solve these challenges.

Great Cthulhu and other Great Old Ones

Cthulhu is mountainous in size. In the tabletop board game of Cthulhu Wars, there’s no problem. Our 8-inch model is easy to see, scary, and makes a great icon for Cthulhu. But in a tactical RPG, sizes are supposed to be accurate. So, no one can make a figure big enough to be Cthulhu himself! (I once calculated that he is a minimum of 100 meters tall, which means at this size his figure would be the height of a real person). So how can we portray Cthulhu without a figure? In addition, Lovecraft makes it abundantly clear that people have no chance against Cthulhu – his arrival is an extinction level event.

Other Great Old Ones and Outer Gods represent similar difficulties. Having players battle and defeat the King in Yellow is … anticlimactic. So what we have done is to turn these super-beings into what amounts to an environmental effect. Each has several “stages” to progress through, each more dire to the world around them. These stages represent the Great Old One becoming more immanent, more real, until the final horror when he is there fully in person.

For example, Cthulhu changes the geometry of the universe by his presence at Stage One, Cthulhu changes the geometry of the universe around him, increasing the reach of his minions, and decreasing that of the heroes. At Stage Two, the physical world changes – escape paths become dead-ends or circles, and so forth until at Stage Four, people can stumble through odd angles into other planes of existence and horrific monsters are oozing through cracks in reality. Similarly, Cthulhu has a telepathic effect that increases by Stage. At Stage One, fear grips everyone as Cthulhu’s mind contacts theirs. At Stage Four, people who fail to resist become Cthulhu’s willing slaves. Other Great Old Ones have similar effects. There is always a nucleus, or center point, that can be attacked or otherwise targeted in an attempt to push the Great Old One back to a weaker stage, and eventually cause it to retreat from reality, at least temporarily.

In this way, players can thwart Cthulhu and yet feel that he was a terrifying, growing, threat that could easily have overthrown the world. And that may yet return!


We have sought to do justice to the other creatures of Lovecraftian lore – treating them as more than piles of stats. For instance, those familiar with the Mythos know flying polyps are one of the most terrifying species Lovecraft ever described, with a history to back up their reputation. Lovecraft states that they caused the extinction of the dinosaurs, for example! The flying polykps are genius-level predators with terrifying abilities. They shift in and out of visibility, and at any given time much of their existence is on other planes of existence. Their polypous, gestalt nature means that the various parts of their body are not necessarily even adjacent to one another.  

In our Pathfinder rules for the flying polyp, the polyps can manifest as several separate bodies which can move and maneuver independently, but each is a part of a single polyp. Thus, this one monster can surround a party, or try to split it, using its bodies as tools! Thus, the polyp becomes a dynamic tactical challenge, unlike any other. A creature with multiple bodies, each shifting in and out of existence.

The Children of Yog-Sothoth are prominent in Lovecraft’s story The Dunwich Horror, in which the interdimensional Yog-Sothoth fathers two children upon a wizard’s daughter.  One of the children can pass for human, at least when wearing long pants and shirts that button up to the neck and wrists, though there is still obviously something wrong with him. The other child is an oft-invisible, mix of tentacles and jointed limbs bigger than an elephant.

We wanted these creatures in our game, so to represent them, we gave them three categories. One (the weakest) is the Mutant, representing the nearly-human hybrid. The Spawn of Yog-Sothoth represents the other end of the spectrum – the colossal, insect/octopus Thing that appears only at the end of The Dunwich Horror. We also created an intermediate stage, balanced between the extremes, and we named this the Abomination. But really, all represent the order of being – a cross between an Outer God and a human.

But in the story, there was more to these entities than simple gross monsters – they are not created by a whim. No indeed, the Outer Gods spawn them for a purpose – to open the magical gateways that can bring them to the world, where they can rule again. So, these entities are always acting and plotting and working and evolving physically to bring about this final apocalypse, which means of course they make terrific opponents for a great horror-based campaign, in which the heroes must stop them to prevent the final catastrophe.

In this way, we have sought to bring Lovecraft to life, combining horror and heroic fantasy in a satisfying way.


Sandy got his start in the game industry at Chaosium in 1980, working on tabletop roleplaying games. His best-known work from that time is the cult game Call of Cthulhu, which has been translated into many languages and is still played worldwide.