Who is the character Zero's enforcer, the giant, and how does he fit into the John Wick universe?

Zero's enforcer and the giant in the John Wick universe is a character named Ernest. He is portrayed by actor Boban Marjanović.

Ernest is a member of the High Table and serves as Zero's right-hand man. He is also known as the 'Adjudicator's muscle' and is tasked with enforcing the rules of the High Table.

Ernest's imposing size and strength make him a formidable opponent, and he plays a key role in the action scenes of John Wick: Chapter 3 - Parabellum. His loyalty to Zero and the High Table is unyielding, and he is willing to do whatever it takes to ensure their interests are protected.