Here is an overview of Yanfei, via the Genshin Impact official website:
Yanfei (voiced by Lizzie Freeman in English, Yumiri Hanamori in Japanese)
A half-illuminated beast and highly-skilled legal adviser.
She combines adherence to the legal codices and reasonable flexibility to find the perfect balance in her work. She devotes herself to protecting the fairness of contracts in Liyue with her identity as a legal adviser and her unique experience and methods.
Watch the trailer below.