The Adjudicator in "John Wick: Chapter 3 – Parabellum" is played by Asia Kate Dillon. The Adjudicator is a representative of the High Table, the powerful council that governs the international assassin's world. They are sent to enforce the High Table's rules and decisions, demonstrating authority and impartiality. The Adjudicator plays a key role in escalating the conflict and challenges faced by John Wick in the movie.