She's never going to change,you know the cycle and patterns of her behavior. It's up to you to choose how you are going to respond. Are you going to continue being her victim or are you going to free yourself from the clutches of her psychological manipulation and abuse? You have to change your response to her abuse. Narcissists can't change and therefore they lack the ability to adapt to it. If you change your tactic they will get agitated and fight harder using the same tools of manipulation that they've used all their lives except now they don't work because your new approach is new.
For example when narcissistic female criminals are interrogated they try to use their sexuality to manipulate the detectives but detectives are trained to focus on the facts. This flusters them when they realize their seduction act isn't working. They then try to seem like victims but good detectives aren't swayed by emotional outbursts, tears and self victimization. I suggest you watch the interrogation of Jodi Arias and you'll see what I mean. She used every manipulative tool she had and they each failed.
That's how you disable the power of narcissists, you place them in an environment where none of their tools work. You have to do to your mother what Netflix did to Blockbuster, change the environment and make her obsolete.
Think back to your early childhood,think back to how she made you feel. Was she cold to you? Did she make you feel like you don't deserve love? Let me tell you something about children,they lack context for life. Children lack understanding so when their questions go unanswered they blame themselves. When children are being neglected they blame themselves because they don't know any better. In reality the child is being neglected because the parents are unfit. They are the ones to blame. They are the ones who failed.
You needed and still need a mother but your mother's NPD means that she is incapable of being a nurturer,self sacrifice and love. She cannot define you because she is incapable of seeing anyone other than herself. She actively fought against and sabotaged your growth because that is the nature of her personality disorder,many animals view their offspring as threats. People with NPD have many anti social traits which they share with animals that lack social empathy.
I say all of this to say that the odds of you having a healthy relationship with your mother were doomed from conception.
You have to find your inner child and make sure that she knows this, understands this because she still blames herself for everything that has ever gone wrong with her. Protect her in the way she should have been protected. Love her they way you wish you had been loved and free her from the clutches of your mother's abuse by removing the last weapon she has,the ability to attack that inner child and keep her dependent on her love. Give your inner child true love by telling her that nothing the monster says is true. Tell her that you defeated the monster and you won't ever let it hurt her again. Slay the monster by taking it's power. Only you can save your inner child and once she is free she will never again have to be a victim.
It's time for you to detach her emotional dependence from your mother and connect her to you,the only adult worthy of loving and protecting her. It's up to you to heal her. Acknowledge her pain because no one did when she was growing up. Talk positively to her,take her out to do things she wished she could've done,even if it means buying a toy she always wanted and play with it. I know this seems weird like I'm trying to get you to split into two separate egos but that's not it. I'm merely advocating for your unresolved childhood trauma that must be addressed to help you live a healthy well adjusted life. Addressing this trauma can help free you from unhealthy relationships because until you give your inner child the validation she needs and deserves she'll keep looking for it in the wrong places. She'll keep getting hurt. Someone has to give her the attention she deserves, hasn't she suffered enough? Childhood neglect unfortunately evolves into adults neglecting their own mental and emotional health because that's what they were indirectly taught. It's up to us as adults to find new tools in order to grow from our trauma.
The next time she goes off simply smile and say "you have no power here" and nothing more. Calmly and then just disengage.
Alexa play Black bird by the Beatles.
Blackbird singing in the dead of night
Take these broken wings and learn to fly
All your life
You were only waiting for this moment to arise
Blackbird singing in the dead of night
Take these sunken eyes and learn to see
All your life
You were only waiting for this moment to be free
Blackbird fly
Blackbird fly
Into the light of the dark black night
Blackbird fly
Blackbird fly
Into the light of the dark black night
Blackbird singing in the dead of night
Take these broken wings and learn to fly
All your life
You were only waiting for this moment to arise
You were only waiting for this moment to arise
You were only waiting for this moment to arise