Feat: Parry and Riposte
Your parries and finishers allow you to riposte with the slightest provocation.
You can use Opportune Riposte against an enemy who fails at a Strike against you (not just critically fails), provided you have both damaged that creature with a finisher on your last turn and currently have a circumstance bonus to AC from the parry weapon trait or Extravagant Parry.