Dr. Angel Morgan, president of the International Association for the Study of Dreams, explained in article for HuffPost, "Our ordinary dreams tend to be symbolic, using metaphors or puns to tell a story about what we are feeling and experiencing that concerns us most at the time of the dream. ... For example, if someone has experienced violence in waking life, then yes violence can make its way into that person's dream because they need to process and eventually heal from what happened."
If you have a violent dream, it could also represent some particularly intense feelings, especially if the dreams involve somebody you know. Violent dreams can be due to past traumatic experiences, or simply because violence has been on your mind. As psychologist Chris Cortman told online counseling website Thriveworks, "When it comes to dreams, always remember that they are born from the material inside the dreamer's head."
The media we consume during the day can impact our dreams too, so a violent dream could follow a nighttime session of watching violent movies or TV shows, as an Ohio State University study found (via ScienceDaily). Dr. Morgan also suggested that the brain uses imagery from violent shows, movies, or videos games in an effort to help us. "When we don't identify as violent people in waking life, our dreaming minds often use gladiators or others we recognize as killers, to do the dirty work and help us 'clean house' in dreams," Morgan continued.