To the outside world, they are the very embodiment of confidence, feel they have been there, done that, got the T-shirt and they don't need any development.
Behind the facade they are unlikely to be as good as they think, with their self-awareness inversely proportionate to their self-confidence.
When things go wrong, of course it is not their fault, it is a plot against them.
Narcissists operate, from a neuroscientific level, from the "primitive" part of their brain and they are fixated on their own survival rather than others.
Unfortunately it is not easy or quick to deal with, 360 degree feedback can be helpful but it can take a long time with a multiple "attack" from different fronts, a few people that can coach/mentor and re-iterate how things are in your own company.
What difficult personality are you dealing with at work?