Thank you for this thorough narc-splanation (feel free to use that one, too...)! Years ago, I dated a tried and true narc, and your description fits to a T. I spot those types from 10 miles away and against strong headwinds by now. My ex didn't ping that radar...
Because...enter stage left...the vulnerable narcissist. And that's where the mindf*ckery turns pro. Vulnerable narcissists--as opposed to grandiose narcs--tend to exhibit and feel loads of emotions. In fact, they're prone to depression and anxiety, can become quite clingy, moody, sad, even histrionic at times. There is none of the overt lying, (obvious) cold-heartedness, psychopathic staring, flashy entitlement, etc. as you'd see in someone of the grandiose type.
The key difference here, it seems, is that the environment mostly confirms the grandiose narc's inflated sense of self-importance, uniqueness, and entitlement, leading them to walk through the world as if their piss doesn't stink. Not so with the vulnerable narc. Their distorted self-image is most often questioned by society (maybe they're not as talented, pretty, smart, or successful as they believe they should be,) leading them to bouts of deep depression, triggered states, isolation, anger, anxiety, and so on.
The issue (amongst a billion others, of course,) is that they tend to have to work a lot harder to "get their supply," so they often appear quite sincere, empathetic, and agreeable. Their mask virtually never slips completely--they're too afraid of being found out--so they've perfected the whole manipulation dance, along with their sad pity party, poor me, "listen to my sad story as an excuse for my bad behavior and anger issues" tactics to elicit empathy and keep their victims hooked.
...and you can see where this is going. Because symptomatically, it can closely mirror BPD and, quelle surprise, PTSD (though to a much lesser degree, as there should be none of the gaslighting and crazy-making going on here.) When someone's depressed, isolating, angry, anxious, or hysterically crying in front of you, hitting themselves in the head, then screaming at you for something you didn't even say, then tell you it's a flashback...well, it's virtually impossible to say whether this person is seriously experiencing flashbacks, just got triggered because they thought you're leaving them or got too close or reminded them that they have no sense of self (BPD,) or you injured their fragile narcissistic framework somehow (narc narc narc.)
When they're isolating and "need space," it's impossible to tell if they're trying to calm their nervous system (PTSD,) are off in a self-righteous rage of push-pull (BPD,) or distance themselves to punish and manipulate your emotions while devaluing you in the process (narc narc narc.)
And to make this shitshow of a Cluster B party even more insane, all three can be present in one fun-filled package.
At the end of the day, I can't 100% be sure I was dealing with a narc. It's a bit like wearing different colored sunglasses. Depending on the shade, the whole thing can look either regrettable and heartbreaking (PTSD,) untenable and crazy-making (BPD,) or full-frontal psycho (narc.) All I know is that this wasn't "just" PTSD. And I wish I'd known that sooner.
I guess I'm going into this level of detail because I think it's important for all supporters to be clear on who and what they're dealing with and to be VERY mindful of what PTSD is and what it isn't; that just because it walks like a duck and quacks like a duck, it doesn't mean it's not actually feathered cyborg duck from planet narcopath. The main difference being: empathy is wildly misplaced when dealing with a narc or untreated BPD. Empathy is required when dealing with PTSD.
