Yes, I think I see. So, on pg 4, when a character sustains a Wound, reduce Rank. Monsters are considered characters. If a Demon Boar takes a Wound, it is reduced to Rank 8, etc. On a Complication, it states, deal weapons Harm, not just 1 Harm. Monsters are reduced in Rank until 0, then dead. Wounds reduce Rank. Harm chips away at the current Rank. Monsters are not impacted by Fear or scars, those are indeed player facing effects.
On pg 29 it says: at 0 health, adversaries are removed from battle. So once at Rank 4, if it takes a Wound, it is dead. Or if it takes a total of 4 harm, then it is dead.
Does this help?