Enemies that weapons have an inherent familial damage bonus against will deal that percentage of damage that is unhealable by any source(well maybe except lichen combination). It's basically permanent damage that reduces max health.
So for all these specialized weapons, the player would deal 12% unhealable damage, and eventually kill these monsters regardless of dem healz.
For example, if one used the Cautery Sword against RJP, eventually one'd be able to kill it by accumulating that 12% of damage over time.
Applicable to Cautery Sword, (Heavy) Deconstructor, (Wild) Hunting Blade, Wrench Wand, Blackhawk, Silversix, Sentenza, Argent Peacemaker, and 0*/1* family-damage weapons (EDIT: I forgot Cold Iron Carver/Vanquisher :|)
Could be applicable to armors, but eh iono.
It's a really niche application, but I like it.
What makes it especially cool is that reducing max health of an enemy would also make them easier to flinch.