This is an interesting article explaining the roles that your story characters need to fill in order to help move the plot along without being a deadweight. This approach helps if you’re trying to create a world for your story and beyond. Instead of just giving them different personalities, define their purpose inside as well.
Many writers don’t understand the importance of dramatic functions, or the usefulness of archetypal characters. One reason is that every novelist has a slightly different schedule for creating characters. Some writers start the novel writing process by inventing a group of characters whom they find interesting. Then they imagine putting those characters into situations or confronting them with problems that will force them to act and interact. Out of this action and interaction a plot will eventually emerge. The characters will, in a sense, “choose their roles themselves.” (Of course, quite often these roles end up being those typically performed by archetypal characters.) Nonetheless, this method can produce characters that are wonderfully original.
Of course, the downside is that you can grow very attached to your characters before your plot has gelled. Consequently, you may be reluctant to cut characters that need to be cut when you discover they serve no essential function in your plot – or fail to include characters that fulfill necessary dramatic roles.
Full guide here: Archetypal Characters