Narcissism, also called possession by the Jezebel Spirit, is the very Biblical definition of Evil. I think we can draw the line for lovable BEFORE a person sells thier soul to demonic forces for the "freedom" to inflict severe emotional, mental, verbal, and spiritual abuse onto others without remorse. I learned my lesson going back for ever increasing abuse 6 times over 10 years. If you want to risk your sanity, your emotional well-being, your sense of self, and your other loving relationships to PROVE these EVIL former humans are lovable, go ahead, good luck. There's a reason they don't want or seek therapy. They seek to do as much damage to as many people as they can as deeply as they possily can in service to evil. People with extreme malignant NPD enjoy the evil acts they perpretrate on others. That's not lovable. Thinking of them as evil gives an appropriate warning to other decent humans to not underestimate them as you do.