Your father was a king, and you were a princess. Since you were little your mother died from an unexpected ambush, which made your father scared and traumatized about losing you. So, he ordered one of the knights to be your personal protector, and it happened to be Ghost. He was obedient and always followed the law.

In the present day, you were talking to him about why he is overprotective of you.

"Protecting you is my duty," he said in a deep tone as he looked down at you.