Horrors are repulsive beings that are completely alien to the world of Dominions. A few have some history with the world, but the vast majority are unknown to the existing civilizations of this Earth; even the likes of R'lyeh have a poor grasp of them. Diligent efforts in the past, by either the last Pantokrator or possibly an earlier one, have made Horrors little more than nightmares in most places. Still, the Horrors are ravenous beings, and they will find a way to push past such barriers for those marked with their favorite flavors.

Horrors cannot be recruited form anywhere, and there is no way to summon an allied one. In battle, Horrors will largely prefer to attack the Horror-Marked, and they disregard the Mindless almost entirely; not that they won't attack if their preferred prey are absent.

The most common Horrors are those who assassinate Horror-Marked commanders. These are the most visible of the Horrors, anyway; assassins automatically win if they somehow assassinate troops, after all, with no battle report. Most (if not all) of these Horrors disappear immediately after succeeding, and revenge cannot be enacted against them.

Each turn, any non-Mindless unit has a chance to be attacked by Horrors. Going off the Dominions 5 formula, the process for determining an inconspicuous commander's risk is as follows:

• Start with 1.
• Add 1 for each point of local Magic on the scales. (For Drain, subtract instead.)
• Add 1 for each point of local Misfortune on the scales. (For Fortune/Luck, subtract instead.)
• If they're Cursed, add 10 for each Horror Mark on them. (Yes, these stack.) Otherwise, add 5 for each Horror Mark on them.
• Multiply whatever the value is at this point by the "Global Horror Level".
  • It's usually 1.
  • 2 turns before the Cataclysm, it's 5.
  • 1 turn before the Cataclysm, it's 10.
  • If Astral Corruption is up, it's 10 (if not already higher).
  • During the Cataclysm, it's 20.
• Call the value at this point "A".
• The commander has an A-in-1000 chance of being assassinated by Horrors each turn.

You (your Pretender God form) and your friends in the Hall of Fame have a higher likelihood of being attacked, due to certain especially-evil Horrors that will be covered somewhere below.

Astral Corruption and the Cataclysm also add a separate chance for Horrors to get fellows, through whenever they spend gems outside of combat. No one knows why they don't attack during combat. They also don't attack during Empowerment or Gem Alchemy. The odds are calculated through the following:

• Start with 1.
• Add 20 for each Horror Mark on them.
• Add 1 for each point of local Magic on the scales. (For Drain, subtract instead.)
• Add 1 for every gem spent in that specific action.
• Call the value at this point "B".
• Roll an exploding die to determine whether or not the attack actually happens:
  • During the Catacylsm, roll an exploding d17; the attack happens if B beats this value.
  • Otherwise, roll an exploding d35; the attack happens if B beats this value.

The above formula is entirely sourced from Dominions 5, and might not be entirely correct.

While few know anything about Horrors, they are nonetheless classified under three tiers: "Lesser", "Greater", and "Doom". For the purpose of the elicit Blood Magic that summons Horrors, "Greater" Horrors are simply known as "Horrors".

Most attacks by Horrors are perpetrated by "Lesser" Horrors, at least for most of the game.

Most of the time. In fact, Lesser Horrors typically come in groups. When you cast Call Lesser Horror, or Send Lesser Horror, you typically call two or three; or, if you end up getting the most human-like of them, around six.

Greater Horrors (such as the aptly-named "Horror") are always called by the highest-end Horror-summoning spells. They may also take the place of the Lesser Horrors when a typical assassination/attack happens. This is far more likely in the case of those gem-baited attacks that only happen during Astral Corruption or the Cataclysm; in these, your attacker has roughly a B% chance to be a Greater Horror, instead of a Lesser Horror.

For regular Horror attacks, the following formula is used instead, at least according to Dominions 5 code-peekers:

• Start with 3. (It may be 5 now, due to how scales were changed.)
• Add 1 for each point of local Drain on the scales. (For Magic, subtract instead.)
• Multiply the value up to this point by 5.
• Add 20 for each Horror Mark on the guy drawing in the attack.
• Add half of the Global Horror Level, rounded down.
• Multiply the value up to this point by half of the Global Horror Level (un-rounded), then round down again.
• Call the value at this point "G".
• The attacker has a G-in-1000 chance of being at least a Greater Horror, instead of a Lesser Horror.

The Doom Horrors are unique beings who, in most cases, rival even the most combative of Pretender Gods. Being unique, they cannot be in two places at once; thus, if a Doom Horror is on the field, they won't random attack a commander. On that note, Doom Horrors have a special desire against the Thrones, implying that they can perhaps attack entire provinces (or at least linger past their assassination attempts). Since there is only one of each of these psychos, Doom Horrors are far rarer than the rest, though two have "favored prey" that they are significantly more likely to take.

In the case of gem-baited attacks during Astral Corruption or the Cataclysm, the attacking Horror has roughly a (10 x B / 25)% chance to be a Doom Horror instead of a Lesser Horror. This is checked before whether or not the Horror can be a Greater Horror; thus, if they're not a Doom Horror, they then have a B% chance to be a Greater Horror instead, and they'll be a Lesser Horror (or a group of them) if neither chance pans out.

In the case of other horror attacks, there's a chance of the attacker being a Doom Horror instead of a Greater Horror.

• Start with G.
• Divide it by 10.
• Call the new value D.
• If D at this point is lower than the Global Horror Level, make it equal to the Global Horror Level.
• If D at this point is still lower than 3, go ahead and make it 3.
• The Greater Horror has a D-in-1000 chance to be a Doom Horror instead.

Two Doom Horrors, in addition to using the above logic, hunt their prey in a different manner.

Umor - Eater of Gods checks Pretender Gods especially closely. Each turn, a Pretender God has a 0.5% chance to be attacked, plus 0.1% for each Horror Mark on them. With either Astral Corruption or the Cataclysm active, Horror Marks add 1% instead. Umor cannot attack Pretender Gods without Horror Marks unless either Astral Corruption or the Cataclysm is active, however. He also cannot attack the Mindless, and he can only attack one foe in this manner per turn. The maximum chance of being attacked by Umor each turn depends on the state of the game:

• If the Cataclysm is active, the maximum chance is 10%.
• If Astral Corruption is up (but the Cataclysm isn't active), the maximum chance is 5%.
• Otherwise, the maximum chance is 2.5%.

Rarku - Hunter of Heroes checks those with Heroic abilities especially closely, especially if they're currently in the Hall of Fame. Rarku targets prey in a similar manner to Umor, but the odds are different. The numbers are rather unclean, but those on the Hall of Fame are exactly 3.25x more likely to be attacked than those off of it. For those off of the Hall of Fame but with Heroic abilities, they have a 0.2% chance to be attacked each turn, plus 0.04% for each Horror Mark on them. Like with Umor, Astral Corruption and the Cataclysm increase the effect of Horror Marks on being attacked tenfold, and allow those without Horror Marks the base attack rate.

• Unlike Umor, though, Rarku's maximum chance of hitting a specific person not on the Hall of Fame is always 2%.
• At least both Umor and Rarku ignore the Mindless, can't attack two guys in a single turn, et cetera.