I hear this comment quite often from those who go through the torment and cruelty of having a narcissistic sister. From the time they were very young they knew that their older or younger sister detested them and wished they had never been born. Often there is sibling rivalry.One child gets the other in trouble or tells small lies to gain favor with a parent. There are verbal skirmishes, often caused by large difference in temperament and disposition of the siblings.
Here I am talking about a pernicious type of deviousness and cruelty that a narcissistic sister uses to terrorize her sibling. There are constant threats and continuoius lies. "I will tell mom what you did and you will get in big trouble. Mom will throw you out of the house." These threats are based on lies that the narcissist has conjured up. Narcissistic rage bubbles and spurts out like a Vesuvian plume of fire and ash, promising to pulverize and burn everything in its wake. The tormented child protects herself by becoming hyper-vigilant. She has trouble falling asleep. She never knows when a trap is going to be set for her. If the mother is narcisssitic and favors the narcissistic daughter, this little one is confronted with horrendous cruelties. Mom always believes her golden daughter. She can do no wrong. The victimized daughter can do nothing right. She tries her best and it is never enough. The narcissistic daughter takes all of the credit for her siblings accomplishments. This becomes intolerable. Victimized sisters protect themselves by becoming invisible. They are not home much of the time. They visit friends as often as they can. They get lost in books