I have a narcissistic mother who couldn't care less what my emotions are, how much she hurt us children from childhood all the way to mid-adulthood, and how much she, still to this day, keeps on abusing a self effacing enabler of a father who chose her over his kids.
The best way to deal with someone like her is to get out, get out, get out. The troublesome thing about Ns is they're so into themselves they can't see they have a problem, and thus they tend to lay the blame onto everyone around them except themselves. They are the 'victim' and as such, they've done nothing wrong. The best way to deal with them is to limit your contacts with the sufferer and try, as hard as it is, to forgive them because they don't know what they do, as crazy as it sounds, and you need to do it for yourself so you understand your own value. Deep down they're depressed little beings with no hope for reformation, so my best advice is to let them go.