I heard somewhere that the Knight's Armor damage reduction doesn't stack. Meaning that the if you buy all of it, then only one piece actually works. Is this true? I don't want to waste the money getting it if so. Maybe one piece then get something else.
One piece provides a global benefit to any piece of armor you wear. Take the hat for your weapon, Gladiatior's Chest, Arms (Stoneskin if hammer), and Legs, and Knights Boots.