Unrestrained passion of sexual or other nature can be expressed in the dream than brutality and cruelty. The experience of brutality in the dream can be very fear-exciting, until the dreaming recognises that he gets in touch by such a dream with his darker, animal side. Maybe he must finish the fears which brutality causes with him to be able to develop.
Spiritually:
Brutality in the dream can refer to demoniacal actions of the bad person.