I wouldn’t call it a learned behavior. Perhaps, it would be labeled as a genetic. People with narcissistic personality disorder often have inherited it by someone in their family with the same medical history. However, narcissists can learn a few tricks when influenced by their environment. Learned behaviors by definition can be unlearned due to them being extrinsic to that individual, but that differs from actual narcissism which is intrinsic; meaning that is who that individual is
Temperament is hereditary, there is no learning involved with temperament. Introversion, extraversion, aggression, passivity, toleration, stress, etc are all heritable traits.
More than likely narcissistic people will have many victims. They usually will cut their friends and family members from that so called victim. The narc will flip between being three things; hero, victim and abusive.
Narcissists will not stay in victims life’s for long, they come and go, leaving their victim broken, confused and lost. Power and control is their main goal to achieve. Narcissists usually feel the idea that they have a lack of control so they end up controlling other people around them. They’re deepest fears include; being illegitimate, ordinary, and flawed.
Narcissists abuse because they aim to undermined their victims.
I hope this helped :)