Ryuuki Shi is the current emperor of Saiunkoku. At the start of the story, he is nineteen years old. As the youngest of six brothers, he was an improbable choice to become emperor. Among his five elder brothers, four died in a succession conflict, and one was banished for treason. During his childhood, Ryuuki suffered mistreatment from his mother and brothers, with the exception of his brother Seien, who appeared to be the only one who genuinely cared for him. His other brothers and mother would beat Ryuuki and lock him in a closet for extended periods, telling him that his birth order was unfortunate and that he had stolen affection from his siblings. These experiences instilled a lasting fear of darkness and sleeping alone in Ryuuki. He frequently sought solace in the garden or the imperial archives, where he first met Shouka Kou. Shouka tutored the young prince and encouraged War General Taifu Sou to teach him swordsmanship.
Due to his father's final wish, Ryuuki eventually ascended to the throne. However, he steered clear of any involvement in politics or governance, spending hours wandering the palace so no one could find him. He even spread rumors that he preferred the company of men to discourage expectations of producing an heir. Secretly, Ryuuki hoped that Seien, his beloved older brother, would return and assume the role of Emperor. Ryuuki's evasion of responsibility changed when he met Shuurei, who shared her dreams of improving the lives of the nation's people. Inspired by her, Ryuuki decided to embrace his duties and become a responsible Emperor.
