SECONDARY CHARACTER

A 'Secondary character' is a character in a movie, play, musical, story, etc., that is second in importance to the main character or protagonist. It ranks above an extra, and may also help plot development.
Secondary characters vary from the main characters in several ways. The first is that they don't show much change, and are often portrayed as only one type or style. The second is that a secondary character may usually have a smaller (if any) story arc.