Sheng Cai'er is the main heroine of the Throne of Seal/Shen Yin Wang Zuo series. She's an assassin knight with a mysterious background and is also the love interest of Long Haochen.

It was later revealed that she is the Assassin Temple's Saint Daughter, which is the equivalent of the Knight Temple's Scion of Light. She is currently a part of the Demon Hunt Squad 1 after being chosen by Long Haochen