It is not uncommon that a real-life obsession with a certain fictional character (or the person who plays that character) may carry over onto your dream world. However, if you dream about a fictional character, this can be an omen that something from your unconscious mind is about to emerge or be revealed. It may also represent memories, images or scenes from your past that were stirred up by reading/watching the movie/book/etc. that featured this fictional character.
To dream of falling or being in love, or becoming physically intimate in any way, with a fictional character represents your understanding about this character and the feelings that he/she generates in you. Something or someone in your waking life has triggered similar beliefs and feelings.
If you dream about being friends with a fictional character, your dream is telling you that you should have higher self-esteem. You are worth believing in. You need to work on believing that you are a special person. Also consider the themes of the story, and the journey the character goes on during the story, for more clues to your dream’s meaning.... My Dream Interpretation
In dreams, fictional characters that do not exist in everyday life may appear.
For example, you may dream of sharing a birthday party with a twin sister you don’t have in waking life; perhaps a character from your favorite TV show, movie or novel appears in your dreams. All your dreams are connected in some way with your life, so just because these people don’t exist in real life doesn’t mean they are less meaningful in dreamland or have any less resemblance to your waking life. In general, fictional characters exaggerate the qualities found in someone close to you so you can better understand the dynamics of the relationship or situation; one might say that the characters are often one dimensional so that their message is more easily understood. For example, Darth Vader from the Star Wars movies may represent, or highlight, a mean streak that your boss is displaying. And fictional characters can also reflect an aspect of yourself that has relevance to your waking life.
If this is the case, they usually do so to let you know the source of your current problem or to remind you of qualities you didn’t know you had. For example, dreaming about Scarlet O’Hara from Gone with the Wind may remind you that you are tougher and more resilient than you think you are.... The Element Encyclopedia