Luna was well aware, she was the younger sibling and she could act spoiled in front of her brother, Lucas, and ask anything she desire. Be it his clothes or the new gadgets made by their company which she wasn't allowed to have because of her small age.
And she had done it too. Since she was a child her brother has treated her like a princess and would do anything possible to meet her demands.
Even when he was in the closed training, and whenever she demand him to buy many souvenirs for her from the places he had to visit during those harsh training days, he would do it without a second thought.
Luna knew she was the most precious treasure of her brother. He loved her and hold her every word dear to his heart. She was his princess and he was her prince. She had thought her brother would always have her back and would protect her from everything and never consider that her ever-strong prince could also be fragile.