Dreams involving themes of violence, such as murder or revenge, can often reflect inner conflicts, feelings of guilt, or unresolved issues in your waking life. Here are a few interpretations of the elements in your dream:

1. Conflict with Your Brother: The presence of your brother in the dream may symbolize a relationship dynamic or unresolved feelings between you two. The act of trying to harm someone together could indicate shared struggles or conflicts in your relationship.
2. Trespasser: The intruder might represent an external threat or a situation that feels invasive in your life. It could symbolize a fear of losing control or being overwhelmed by circumstances beyond your influence.
3. Use of a Nail File: The choice of a nail file instead of a more conventional weapon may suggest feelings of inadequacy or a struggle to assert yourself. It could imply that you feel ill-equipped to deal with certain challenges.
4. Transformation of the Victim: The transformation of the person you tried to harm into a tyrannical dictator could suggest that unresolved issues can lead to negative consequences. It might indicate a fear that past actions could come back to haunt you or that you’ve created a bigger problem by attempting to deal with a situation in a harmful way.
5. Changing Identity: The act of changing your identity to escape punishment might symbolize a desire to escape from responsibilities or the consequences of your actions. It may reflect a need for change in how you present yourself or how you cope with challenges.

Overall, this dream may be inviting you to explore your feelings about conflict, relationships, and personal responsibility. Consider reflecting on any current issues in your life that might relate to the themes of your dream. It may be beneficial to address any unresolved conflicts or feelings of guilt to find a path toward resolution.