Onward to Rome! A Review of 7th Edition Guide to Cthulhu Invictus

Guide to Cthulhu Invictus

Author: Oscar Rios with William Adcock, Stuart Boom, and Chad Bowser
Publisher: Golden Goblin Press
Page Count: 198
Available Formats:
PDF and print PDF (Golden Goblin Press) – $24.99
Print (Golden Goblin Press) – $49.95
Print+PDF (Golden Goblin Press) – $65.00


Cthulhu Invictus, a supplement for Chaosium’s Call of Cthulhu RPG, has an interesting history. It was initially published as a monograph back in 2004, with designers Chad Bowser, Deane P. Goodwin, and Andi Newton. The idea of Mythos adventures in Imperial Rome was a fascinating one and brought forth a full-fledged sourcebook in 2009 as well as a companion book.

In 2017 Golden Goblin Press launched a successful Kickstarter to publish the 7th Edition Guide to Cthulhu Invictus, delivered in 2018. [Disclosure – I was a backer of the product, though I do not think that has any impact on my opinion of it.] It was written by Oscar Rios with William Adcock, Stuart Boom, and Chad Bowser. It is a color book and the digital version is nicely bookmarked, making navigation very easy. For this review, Cthulhu Invictus will be used to represent the actual book while Cthulhu Invictus will describe the setting.


Cthulhu Invictus is a sourcebook for campaigns in the Roman Empire, with a default year of 145 AD. The book indicates that it would be fairly easy to vary the year, from Republican Rome to the Byzantine Empire. I suspect the truth of that statement is dependent on how obsessed one is with history, but Cthulhu Invictus is certainly a good starting point. For those interested in such undertakings, it is worth noting that the Design Mechanism has Mythras supplements for both Republican Rome and Constantinople – given the similarity between Mythras and Call of Cthulhu, they’d fit in very well with Cthulhu Invictus.

I find it interesting that it is some five centuries before the writing of the Necronomicon. The book begins with an interesting sidebar, discussing why one would want to play Cthulhu Invictus. These reasons are (with my paraphrased summaries):

  • Magic is Real – unlike more “modern” eras, magic is taken for granted in this setting. Some characters may even start knowing some magic. (Note that Mythos Magic is still just as dangerous as it is in other eras.)
  • International Appeal – the Empire is quite cosmopolitan, travel is easy. You might have one adventure in Britain, the next in Egypt.
  • Pulp or Purist – One can run a traditional Cthulhu campaign with deadly combat, sanity-blasting encounters, etc. Or one can go pulp, with characters taking up their weapons and smiting the enemies of humanity.
  • Weapons and Armor – Donning chainmail and a sword is cool.
  • Scrolls and Artifacts – There are lots of pre-human history civilizations, such as Atlantis and Hyperborea, who left behind artifacts to find.
  • Monsters of Mythology – Creatures like Pegasi can be realized in Mythos form.

Assuming one is sold on this idea, how well does the book deliver upon it? Very well in my estimation, with the caveat that I’ve not yet had the opportunity to play it (though this review has me really wanting to…) One of the challenges I find with historical gaming is figuring out what to do with all the information one gets in a sourcebook or RPG. Cthulhu Invictus avoids this problem – it is filled with ideas begging to be used.

The opening chapter provides an overview of life in the Empire – things like social classes, family, money, religion, sexuality, the calendar, education, and entertainment. The section on sexuality, though brief, is interesting, as it describes very different assumptions from current western culture. Homosexual relationships (often with very different ages) were accepted, Emperor Hadrian was quite openly homosexual, and Emperor Elagabalus was transgender. (A little Googling confirmed these details on those two emperors.)

Chapter Two describes character creation rules. There are some changes from Call of Cthulhu 7th Edition rules. Probably the most notable is replacing Credit Rating with Status, measuring a character’s social class, from Vagabond (and often a slave) to the Super Rich wealth of the Emperor and his family. Characters must also be identified as having a rural or urban background, as that will impact some starting skills. Finally, there is a detailed section on Roman naming conventions, with some handy tables.

Chapter Three covers Investigator Occupations – and there are many occupations here. This is useful, given how the core Call of Cthulhu occupations are not really applicable to the Roman Empire. The breadth of the occupations is quite impressive, with professional occupations, like Advocates (essentially lawyers), various kinds of warriors, laborers, mystical characters, political characters, etc.

Chapter Four describes Investigator Skills. Only those skills which are new or changed from the core rules are detailed here. Stealth, for example, is stealth. However, there are several new skills such as Empire (knowing the Empire) or Status/Infamy (replacing Credit Rating, with Infamy representing a kind of “negative status” to show you might be quite well-known but despised). Science skills are quite different, reflecting the Roman understanding of the world.

Chapter Five is about “Life & Death” – combat, poison, and healing. Getting hurt in a “purist” style game is a bad idea, with optional rules for infection. Unlike modern eras, armor is a reasonable form of protection – at least against more mundane threats. However, armor provides a random amount of protection from attacks, meaning even the heaviest armor has its weak spots. Similarly, there are more detailed rules for shield use and parrying. Like in RuneQuest, shields and weapons will wear out as a result of being used defensively. I imagine that Cthulhu Invictus combat would take a little bit longer than a classic game, with armor and weapons doing a bit less damage.

Chapter Six covers the Spiritual World. This includes Roman beliefs, a discussion of the common religions, and philosophical disciplines. It provides an optional rule for faith and luck – more pious characters gain luck back in greater amounts and only need to spend half as much luck as normal. Indifferent characters suffer penalties in the same manner. Being pious does carry a financial cost. While Cthulhu Invictus has the same threats to sanity as a normal game, treatment for the insane is quite different and is covered here. Finally, there is a discussion of the different forms of auguries in the Roman Empire.

Chapter Seven is devoted to magic in the Roman world, including tomes and artifacts. It includes a discussion of fallen kingdoms such as the Hyperborean world of Clark Ashton Smith. In this era before the Necronomicon, new tomes are required and a lengthy list is provided. I especially liked Adventus Regis AuratiArrival of the King in Yellow, being a fan of the Chambers’ King in Yellow tales. An interesting list of artifacts is provided, many of which good fodder for entire adventures or even campaigns.

Call of Cthulhu is known for its horrifying monsters and Chapter Eight provides many more. This list focuses on Mythos takes on legendary creatures. For example, the basilisk is from another dimension and possess a hunting organ, “the paralytic orb”. One of its uses is in reproduction, allowing them to transform a host’s skin to a mineral shell – with basilisk larvae that will feast on the insides before burrowing out. There are many other creatures given such treatments, like centaurs, harpies, hydrae, etc. I suspect it could be possible to overdo using this, where every myth or legend has a Mythos origin, but it provides great inspiration – and in a pulpier campaign, why not use all of it?

I suspect Chapter Nine will be particularly essential for Invictus campaigns – it covers cults, patrons, and investigator organizations. This gives a variety of potential enemies, like Heralds of the Deep – worshippers of Cthulhu, including Deep Ones in their midst. Patrons give investigators access to powerful allies. And Investigator Organizations provide for a way to get and keep investigators together and provide them with additional resources. Even if one were to not use any of the groups and people in this chapter, it provides great examples when considering “what do I do with all this stuff?”

I’ll consider Chapters Ten and Eleven together. Chapter Ten is all about Roman Legions and their enemies. This includes a breakdown of the legions in various provinces and the weapons of war they use. Chapter Eleven describes the provinces of Rome, including the types of Mythos threats they might face.

Chapter Twelve is “A Very Brief Tour of the City of Rome”. Though only nine pages long (including three pages of maps), it covers the essentials. This includes neighborhoods, the layout (not remotely a grid, unlike some Roman cities), getting around after dark, and the Port of Ostia, located downstream at the mouth of the Tiber River. Famous locations such as the Forum, various temples, and the Colosseum are described. In addition to a high-level map of the city, there are maps of a Roman Insula (apartments), urban and rural houses, and a villa.

The book closes with some NPCs for Kickstarter backers (this was above the level I backed) and a pair of scenarios. The first, “Blood & Glory”, details a mystery involving gladiators during a holiday. The second, “Food For Worms” deals with a plague killing thousands in Rome. Perhaps a zombie apocalypse in the making?


I’ve obviously slipped my opinions in with my description of the book, but what do I think of the whole? To begin, I’m amazed how dense it is. It feels a lot longer than its 198 pages, and it packs a lot of material within it.

I’ve talked about the inspirations that the book provides. I think that’s an essential component of any campaign sourcebook. Reading it, I find myself filled with ideas as to what I could do with it. Just like two classic-era games might bear little resemblance to one another, neither will two Invictus games.

If there’s one thing I find a bit off, it’s how so many legendary creatures are given Mythos origins. This is in some contrast to the creatures created by H.P. Lovecraft, who often had no legendary analogue. However, that quibble aside, the creatures are wonderfully done, such that the core of the legend remains intact, but often going in surprising directions. I’d be hesitant to use every creature there, but that’s just my own personal style.

Who should or shouldn’t buy this book? If you’ve no interest in a game during the period of the Roman Empire (or in the years before and after it), you probably wouldn’t get much use out of it – though the magic and creatures sections might prove useful. However, if you are interested in such a game, I think you’d find it essential. It manages to perform the difficult task of both providing a vibrant setting and a toolkit simultaneously. The mere act of writing this review has me eager to try out a campaign in this era.

~Daniel Stack

Follow Daniel on Twitter at @DStack1776
Join our Discord
We’re on Facebook!

Cthulhu Invictus was chosen by our Patrons to be April’s Patron Choice Review. Each month Patrons take part in a short survey and vote for the next month’s Patron Choice Review. If you enjoy getting your industry news from us, reading our honest reviews, or any of our helpful articles, please consider becoming one of our valued Patrons. Please click the banner above to visit our Patreon site to learn more about how you can help support us and be a part of the Boxcar Nation.

2 Comments Add yours

  1. Froth says:

    Really nice review! I linked to it from my blog this week. Keep up the good work!

    Liked by 2 people

    1. modoc31 says:


      Thank you for the kinds words and sharing Danial’s review your readers. We appreaciate it!

      ~ Modoc


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.