This Means War
One On One?
You vs. this person who has spent a lifetime lying, manipulating and twisting things and people to serve narcissistic obsessions.
Ready or not, you are in a battle; the field is not level, and it's in the narcissist's favor.
If you are surrounded by people who know you and see you as the honest, simple person you've always been, they will either fall under the narcissist's manipulative spells or they'll run for cover to protect themselves from the narcissist's wrath.
Why not just toss it in and walk away from the obsessive narcissist? Because that narcissist is obsessed and fixated on you. Even your "giving up" is not enough victory for the narcissist.
What are you to do?
You'll need to start learning to do battle, and learn quickly.
All your years of mild passivity will not serve you well in this case. This problem will not go away; so be armed and be ready.