That lack of self awareness is their Achilles' heel, more so when they are in higher positions of power: They are unable to recognize when the root of the support structure they depend on is failing, making it harder for them to mend the damage in order to keep their position. In other words, attacking a narcissist directly is pointless (they don't care what you say), instead pick away at their support until it ruptures and they'll have no clue how they fell. The story of Jericho comes to mind.