Now that we're well on our way to building the "what" of the story, it's time for the "who"! Characters are the people--or animals, or robots, or whatever else you want--who participate in the plot. This includes the protagonist, antagonist, and various other roles that fill out your story's cast. In addition to their roles, characters can be divided into other categories, such as Dynamic, Static, Round, and Flat.
Dynamic characters are those who change through the completion of a character arc; static characters do not change in their motivations or goals. Round characters are fleshed out with complex emotions and histories, while flat characters are...well...one-dimensional.
Each character and character type has their place in the story.
For more details on dynamic, static, round, and flat characters, as well as what a character arc is and how to write one, check out the video below!