So you've been managing well with your current skills, dispatching enemies with your familiar attacks and weapons. Now you've encountered a Heavily Armored Mook. Using your basic attacks and abilities you ... fail to hurt the Mook at all. Not good. This can also be turned against the player; for example, if normally their life bar only decreases once their armor bar is depleted, late-game enemies might get attacks that damage both bars at once, or even ignore the armor bar entirely. Examples of Armor-Piercing Attack include: