Who is the character Zero's main henchman, Ernest, and how does he fit into the John Wick storyline?

Ernest is a character in the John Wick movie series and serves as the main henchman for the character Zero, who is a sushi chef and assassin. Ernest is portrayed by actor Boban Marjanovic.

Ernest first appears in John Wick: Chapter 3 - Parabellum and is tasked by Zero to hunt down John Wick. He is a skilled fighter and a loyal follower of Zero, following his orders without question. Throughout the movie, he engages in a series of fights with John Wick and proves to be a formidable opponent.

In the final battle between John Wick and Zero, Ernest is killed by John Wick, but not before proving his loyalty to Zero and earning his respect.

Ernest plays a minor role in the John Wick storyline but is an important part of the action and fight scenes in the movie.