Who's Si Li Li ? Is she the prince of the other kingdom ?

According to this MDL post  https://mydramalist.com/article/the-world-of-joy-of-life - Si Li Li is a Qing royalty forced to work as a spy for Qi because they held her brother hostage.

In Joy of Life season 1 - ep 34, around 27:45 mark, Si Lili confessed that she’s Qing Royalty and her real name is Li Lisi.