Not all the bully persons are narcissists - they can have psychopaths or borderline traits too - but it is also true that adults with NPD (Narcissist Personality Disorder) tend to be bully and abusive and are extremely manipulative. As a professional I know that all of these people had very difficult time in their early childhood, they didn't have the luck to be cared with enough love by their parents/caregivers and didn't have the opportunity to develop an integrated and balanced identity and to learn how to love. This is a fact and not a way to justify their abusive behaviour.
Since nowadays it is becoming very common to give the voice to the people experiencing mental health problems, such as depression, schizophrenia, borderline personality disorder, etc. I have been searching for some data such as videos, interviews, blogs of people who have narcissism talking of their problems, experiences, changes after a therapeutic treatment. I have found a huge amount of videos talking about signs and "bad sides" of the manipulative and abusive narcissist and none video of a narcissistic person. There were just a few blogs where these people have the opportunity to share their troubles (see links below).
I firmly believe that the persons who have NPD can have the chance to change, to learn to really love themselves for what they are and so to learn to love other people and these goals can be reached through the therapeutic relationship. The step someone with NPD does seeking a therapeutic help is the first step to prevent and cure bullyism and abuse, and I want to stress that it is very important expecially for parents who have little children.
Finally, I believe that we need to talk more about it, to talk with those mothers and fathers, workers and leaders, to encourage people whom faced their narcissistic side to express themselves, to tell their experience to give the hope and motivate others to open up and look for help.