Dual Blades and +% pierce dmg

Hi again,

Does the +% pierce dmg from Dual Blades affect other skills, like Shadow Strike and Ring of Steel? Or is it solely restricted to Dual Blades line?

as far as I’m aware;

Dual blades will boost piece (& cold) damage whilst you are dual wielding. Both the % based & flat damage based are applied to your weapon damage, so any skill that has a %weapon damage will be increased by your ranks in Dual Blades!