Just wanted to jump in quick to also just confirm the “attack” is broken down into each component for applying the Orc Armor.
While it is “one move”, within it is each instance of damage, in your example being from the Dust Devil + 3 Ironhawk Troops. So, the Orc Armor would trigger for each.
But y’all beat me to it
Jeto (she/they) - Support Human