What is the role of the character Zero's enforcer, the throwing knives woman, in John Wick: Chapter 3 - Parabellum?

The character you are referring to is named 'The Adjudicator's enforcer' and she is played by actress Asia Kate Dillon. Her role in the movie is to enforce the will of The High Table, which is the governing body of the criminal underworld in the John Wick universe. Specifically, she is sent to help The Adjudicator, who is a representative of The High Table, in their mission to eliminate John Wick and anyone who helped him in the previous movies.

During the movie, she has a few action scenes where she showcases her skills with throwing knives, but her main role is to serve as an obstacle for John Wick and his allies. She is a fearsome and relentless opponent, and her presence adds to the tension and excitement of the movie's action sequences.