Absolute skills

I need to check the manual. Simply, if, in the case of luck, it doesn't rise above 5, then Morale crosses this limit. This allows me to conclude that the probability continues to increase. Although, in practice, this is refuted. Positive Morale is more effective. Undead won't benefit from it :).

Therefore, there are more useful super abilities. For example, "True Luck" and "Arcane Knowledge." They give huge bonuses :)!

The point isn't about which is better, positive or negative Morale.
The point is to remove the entire effect of positive Morale and add the effect of negative Morale (specifically, -10 will eliminate all positive effects and add a negative one).
For example, this is perfect against a Knight. We will not only negate his Morale but also Retribution and Empathy. And it's not just the Knight who benefits from these skills ;)
And True Luck gives an Elf only about a 30% increase to their existing luck (50 with luck = 3), because the Elf will already have high luck by the time they acquire this skill.
Morale, like luck, cannot have more than a 50% chance of triggering. Even with +22 Morale ;)
Now let's see how a Dark Lord will harm a Knight:
The position on the scale varies by +0.5 or -0.5 - this is a purely whole turn between these values, therefore, reducing the enemy's Morale from 5 to -5 is approximately equivalent to an artifact that gives -50% initiative to the opponent. This is two and a half Staffs (the chances of morale appearing/not appearing with different signs cancel each other out when they are equal, therefore it is not 25% to initiative), but this is only after the first turn + the hero's turn.

Therefore, after all the inaccuracies, we can conclude that by reducing Morale from +5 to -5, we get the same effect as two Staffs of the Underworld, that is, -40% to initiative, considering that we can find a Staff on the map, and it wouldn't hurt to have a ring too.... :)
So, "Shriek of Horror" is a normal mega-perk, but with a narrow focus against certain races (the same Dark Lords or Sheiks (opponents) won't benefit from it:( ).
Combined with artifacts, of course, all this is even more effective. But we shouldn't forget that by shrieking, the Dark Lord not only reduces Morale but also luck and initiative. The only thing that's a pity is wasting the hero's turn.
Therefore, there is no need to talk about the uselessness of this ability, as was said before :)