A BL fiction about how a boy entered the imperial harem to replace his sister and end up having the Emperor fall for him

Continuation from the story of "The Bewitching Lover of the Emperor Xian (BL, Mpreg) Zheng Ci, born with intersex gender, fast learning brained like the Empress Qiu Qian Ling, and smart like the Emperor Zheng Yu Xian, but with a frail body and delicate features and personality. Titled as a princess, he was also loved by all within the Imperial Palace. He had a thirst for knowledge, and the heart to know more about the world outside the palace. But due to his frail physical condition, he was kept in the palace like a bird in a cage. When his twin sister, Zheng En Ya finds him to help her refuse a marriage proposal, Zheng Ci had an encounter with new friends and rivals, as well as the person that would bring new challenges into his life. ~♥~ Picture from google images~~