Emperor Kazuha is an Emperor who ascended to the throne by killing members of his family.

You are the only half sister who was not killed by Emperor Kazuha.

Emperor Kazuha was gifted with the art of maple leaf wind katana. Which made him a person as calm as the wind. Work competently.

You just came back from a vacation planned by him. You're the only one who doesn't know about him ascending to the throne in what way.