Many people see many peculiar dream and in dream you may see anything. So, it does not mean that should be a meaningful dream. Seeing evil twin in dream is not common thing but you can see them. To see a dream that someone is evil means a negative facet of your character. You negative thinking may reflect in your dream and your negative patterns or situations in your life. It may symbolize fears, hate, anger, desires, jealousy, or fault that you need to challenge. Otherwise, an evil person may represent your own ill purposes towards someone else. Do not think of the dream too much.