Our Little Empress

The child of a prophecy is born to save the world. "I need to get married to save people…? I'll do the marriage!" The emperor is a young and innocent boy. But… "I can't give you my daughter! She will not be becoming empress." My father interfered with my marriage! "Is my sister just a toy to you?" And my brother too! Will I be able to save the world? This is a oneshot promotional manhwa for the novel of the same name