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If anyone knows the source of this image, I'd love to credit them.

If anyone knows the source of this image, I’d love to credit them.

There are basically three ways to integrate the Cuthuhlu Mythos into an In Nomine Game.

  1. Creatures from the Mythos are powerful and ambitious gestalt spirits that have not yet attained godhood. (Any individual incarnation is manageable, but they keep coming back).
  2. The Mythos is a distant Pantheon of Ethereal Deities. Dangerous, but unlikely to overturn celestial primacy.
  3. The truth of Azathoth is equal to, if not greater than the truth of God and Lucifer. Powerful, malignant, and recently alerted to the presence of the true Corporeal realm.

Since it is Halloween, I have decided to focus on this last scenario.


No Cuthuhlu setting would be complete without Sanity – and in the Nightmare scenario, even Angels stand to lose theirs.

Base Sanity = Will + Precision + Corporeal Forces + 2 for Shedim and Kyriotates

Penalties = Mythos Lore, Highest Ethereal Discord, Highest Celestial Discord*, Number of Discords*, Number of Rank 6 Discords*

When are Sanity Rolls required?

Characters must make a Sanity Roll any time the character studies the Mythos**, uses a Mythos ability, or encounters a Mythos creature that meets or exceeds their own Forces.

This roll follows the standard d666 mechanics (including automatic failures).

Sanity Failure by Check Digit

  1. Your character is paralyzed by dread for a number of rounds equal to your Intelligence/2.
  2. As (1) followed by acting out your highest level Ethereal or Celestial discord.
  3. As (2) followed by increasing one Discord of your Choice
  4. As (2) either gain a new Discord or advance your Highest Discord
  5. As (2) followed by increasing a Discord of your choice AND gaining a new discord.
  6. As (2) plus gain one Discord and increase your highest (non-max) Discord.
  7. You must increase two additional Discords for each point past 6.

Unfavorable Interventions

If you roll an unfavorable intervention on a Sanity check, you must increase all Discords by 1*, take one new Discord for each that was already at maximum*, and advance at least one Discord to the level of the Force that it corresponds to*.

* Geases don’t count unless owed to a Great Old One or Outer God.
** If a Seraph Resonates with a Great Old One the angel will require a Sanity Roll.

The Great Old Ones

In the Nightmare scenario, the Great Old Ones are a hideous combination of Ethereal God and Gestalt spirit. Like the Angels, most range between 9 and 18 forces. However, even when a Great Old One is destroyed in Celestial combat, it will eventually return – either by building a new “Celestial” vessel over the course of eons, or by migrating to the next most powerful incarnation of itself.

Although they are Ethereal Spirits, the Great Old Ones often function like Word Bound spirits that embody themselves rather than any earthly concept. Should an Ethereal spirit (or even a Celestial) become the Servitor of a Great Old One, it will start to take on some of its masters characteristics.

Many of the Great Old Ones incorporate the Emotional Element of Dread. This makes them especially deadly to other Ethereals, who tend to scatter in the presence of the Great Old Ones, and can justify modifiers to the Check Digit of a failed Sanity roll.

The Outer Gods

If the Great Old Ones are the “Servitors” of the Mythos – the Outer Gods are it’s Superiors. Their powers are vast beyond compare, and though they can be defeated – their destruction should basically be outside the scope of the story. Some of these entities channel power down to Great Old Ones, or occasionally even lesser beings – but most are puissant beyond caring and leave it to Nyarlathotep to manage such things in their stead.


Like their Celestial counterparts, the Outer Gods can be summoned.

Base Invocation: 0

Invocation Modifiers
+1 Per Element incorporated into ceremeony
+1 Per Sanity lost via voluntary increase in Discord
+1 Per 2 points of Essence spent (the Outer Gods prefer Sanity)

Possible Elements

Nyarlathotep: Cosmos, Dread, Deception, Nations, and Research
Shub-Niggurath: Cosmos, Dread, Life, Survival and Chaos
Yog-Sothoth: Cosmos, Dread, Portals, and the Outsider

Should any of these Spirits be called to Earth, it will create a magnitude 50 disturbance and profoundly warp whatever space was used for the summoning.


Inside the Nightmare scenario, Azathoth is at least as powerful as the God of Heaven. It gains the same protection of Ineffability as God and Lucifer, and can probably transcend some (though maybe not all) of the limits that the GM Guide gives to Lucifer’s power (pg 116).

It’s Worse Than You Think

Of course, if you really want things to be bad – it’s entirely possible that the God of Heaven is Azathoth. After all, no one who has ascended to the Higher Heavens has ever returned to tell the tale…

Chaoseum & Steve Jackson

It is unlikely that we will ever see an official Call of Cthulhu expansion for In Nomine, because the former title is licensed to Chaoseum and the later owned by Steve Jackson. There isn’t even a Cthulhu GURPs module (which is saying something). However, Steve Jackson games does have some unofficial suggestions. Combine those with GURPs Horror and GURPs In Nomine and you should be good to go.