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?