The narcissistic personality type person is probably one of the most difficult people to deal with. You pegged it correct. No remorse, no sense of compassion for any one else's feelings. They move from relationship to relationship getting their 'supply' of whatever it is they need at the time. They morph into whatever they need to be, wherever they are, to get their supply (hence the ability to sound like an anarchist). They are masters of the guilt trip & silent treatment. When they have 'used up' the supply, they move on. I am sorry you had to go through this.