Evil manifestations in dreams will nearly always represent something in yourself. Don't be offended: there is evil in everyone. What needs to be understood is that the same psychic forces may be good or evil - that is, they may work constructively or destructively.
Evil (destructiveness) rises up from the unconscious, where we bury the parts of ourselves that have at some time frightened us or caused guilt-feelings. We mostly project these repressed psychic drives or qualities on to other people, and this may be what your dream is saying you are doing.
Anger, hatred, and all other destructive tendencies can be dealt with only in oneself. The key to success in dealing with this evil within ourselves is to realize that what is evil is potentially good. Accept the neglected and feared things in yourself, let them assume their proper destined role in your life, and they will then be a power for good. Evil may reside even in what we call our 'conscience'. Conscience may be of two kinds: a repository for socially accepted norms of behaviour, including notions of right and wrong picked up from parents in our early years; and a medium by which the conscious ego can receive promptings and warnings from the centre of your being. The latter may sometimes conflict with the former - what your 'destiny' calls for may be at odds with what society demands - and courage may be needed to remain true to your inner self. Since we are all in process of evolution, we cannot properly expect perfection in ourselves or others. An unbending perfectionism is a neurotic condition. The essential thing is to be aware of the evil in ourselves. Only thus can we control it; otherwise, it will control us. Beware of the person who thinks he or she is perfect! Self-knowledge is the first step towards solving the problem of evil.