"Necropolis" - changes to creatures of levels 6-7.

and what is the difference between "Horrific Presence" and "Attack with Fear" - as far as I understand, it's only in the name.

If I'm not mistaken, "Horrific Presence" is the name given to a super ability here, compared to which the current "Wail" is child's play.
50% chance that instead of attacking these creatures, the enemy will flee in fear (affecting the mind), +50% turn at the beginning of the battle.

"Horrific Presence" - frightens the squad that is standing nearby and trying to attack.

If this is the ability I'm talking about, then no. Absolutely any squad (nearby or not) that tries to attack these creatures is frightened. More precisely, it may be frightened with a 50% chance. It's similar to "Ethereal," but worse. Units with this property are usually invulnerable. I've seen this ability in action because in my mod, it was given to the Horror Dragons (which I didn't remove in favor of the steeds) and the Fiery Nightmares.