Narcissists Are Bullies
Bullying has always existed in one form or another. It's often associated with children in school, but many people are using it to address problems between adults as well. We often hear that bullies are people who are unhappy and taking their misery out on other people. With narcissists at least, that's definitely true. Many of them are miserable and the only way they know how to get relief is to spread it around to others by hurting them. This is an unhealthy coping mechanism that allows the person to feel better by taking the focus off of their own pain, and by putting others down so they can feel better.
In fact, narcissists do this so routinely that they often accuse others of doing the same thing, of putting others down to make themselves feel better. They seem to believe that this is how everyone operates. They feel that you intentionally hurt them and they believe it's because you are lacking somehow, which is of course, exactly the way that they operate. They don't seem able to understand or believe that not everyone's sense of self-worth is so deficient that they need to devalue others to feel like they themselves are worth something. They can't seem to realize or accept that not everyone feels bad the way they do, and not everyone needs to hurt others to feel good.
Narcissists also bully others because they are very concerned with power and control. On the inside, these are people who feel very powerless and that they have control of nothing, including themselves. The controlling and domineering behavior that we often see from pathologically narcissistic people is an overcompensation for this internal weakness. They exist in a reality where everyone is desperate to control others - mainly, to control the narcissist. They seem to believe their freedom and individuality is being usurped by other people, or that others are waiting for the opportunity to control them.
This is probably because they feel greatly influenced by and dependent upon other people in general and place all the responsibility for themselves on others. Because they place the responsibility for their actions and feelings on other people, because they rely on others for their self-worth and because they have an unstable sense of identity which results in them either consciously or subconsciously emulating people around them, this can cause them to feel like they are being controlled by others. In order to counteract that feeling of being controlled and helpless, they often overreact with displays of power and dominance.
Finally, narcissists engage in bullying behavior because they are immature and want their own way. They are very reward-oriented and when they are told no or that they can't have something, they react with rage. They will often use anger, violence, guilt and whatever else they have to in order to get their way. Pathologically narcissistic people usually have a very hard time with their emotions and they cannot tolerate frustration. It's like dealing with an adult-sized toddler.
If you are dealing with a narcissistic person and are being mistreated or bullied, remember that you don't have to put up with it. There are ways out of the situation. Above all, don't let the narcissist make you feel that you are powerless simply because they feel that way. You aren't. You've always had the power. You just need to remember that.