But what does it mean to be a compelling character? Some distinguish between round and flat characters. A round character is a complex, often conflicted character with a deep internal life who usually undergoes some kind of change over the course of the story. A flat character lacks that complexity, does not change at all over the course of the story, and is usually there only to help the more round characters on their journeys.
Round characters feel real because they grow and wrestle with conflict, while flat characters are more like support beams holding up the main story.