The name could be "Nightmare Dominion" or "Dread Empire." The empire could be ruled by a powerful and malevolent leader who rules with fear and terror, oppressing the citizens and spreading darkness across the land. The inhabitants of the empire are constantly living in fear of the ruler and his cruel regime, with nightmares plaguing their every waking moment. The empire's symbol could be a menacing, twisted crown surrounded by swirling shadows, representing the oppressive and nightmarish rule of its leader.