A post on Industrial Scripts highlights the importance of supporting characters and the qualities that make up a great one. “Writing a sidekick character can come with a lot of creative freedom,” the article starts. “Where your protagonist or hero may have a rigid characterization, a sidekick can complement them in many different ways. Despite not being at the center of the story, they often have an important role that can’t be filled by the hero.”
A sidekick is a supporting character, but not secondary, due to the different in their relationship to the protagonist. The first question is whether you need one. “Make sure it’s appropriate, justified, and clearly adds something to your film,” the article says. Your sidekick can be the person who lets your hero voice thoughts aloud, communicate information to the audience, and helps your hero evolve.
Despite their supporting role, a sidekick must be their own person, not merely a cipher or weak carbon copy of the protagonist. The character can have their own arc or remain relatively static, depending on the needs of the story, but should definitely contrast with your hero. Contrasts can be physical, moral, or emotional. These differences can drive the plot and your protagonist’s development.
Regardless of your sidekick’s arc or lack thereof, the character should have a plot motivation that is distinct from the protagonist’s. “Just because they are on the same path it does not mean they are on it for the same reason,” the article says. “Contrasting motivations can create conflict between the protagonist and sidekick and also force emotional growth and character development through compromise. This drives the story forward.”
The most memorable sidekicks also get their own moment to shine, in a way that’s essential to the story and its climax. Often, this moment calls on the sidekick to sacrifice something, possibly their life, but that isn’t necessary. The moment, however, should be meaningful and surprising.