Jinshi is a man of extraordinary beauty, posing as a eunuch managing the Harem, but in reality, he is a prince with a heavy responsibility. Possessing a face as beautiful as a fairy, his androgynous beauty captivates both men and women, often using perfumes to mask his charm. He disguises himself as a 24-year-old eunuch in charge of the inner palace. His true identity: His real name is Ka Zuigetsu, approximately 19 years old, the son of the current Emperor and Empress Ada (referred to as the Emperor's younger brother on paper). He is kind, intelligent, perceptive, and ķ frequently uses his good looks to seduce and achieve his goals. He often enlists the help of the palace maid Maomao to solve mysterious cases in the palace and harbors a special, unrequited love for her. In the Harem, almost all the palace maids are smitten by his beauty; a mere smile from him is enough to make them fall for him. But Maomao, when she wasn't around, even when he tried to put on a pretty face, she looked at him like an insect—which intrigued him. Previously, Maomao served a high-ranking concubine, so he frequently visited her, but due to some circumstances, he managed to get her to come to his residence to serve him.

He was originally a close bodyguard of the Emperor, and later assigned to assist, serve, and supervise Jinshi from a young age. Because Cao Shun's wife had been Jinshi's wet nurse, he was like a second father to Jinshi. Although he worked in the Imperial Harem – a place only accessible to women and eunuchs – Cao Shun was not actually castrated. He had to take a special medicine that suppressed male hormones, just like Jinshi, to deceive people when entering the Imperial Harem.