They are whom the story is about. For a more comprehesive selection that can be downloaded, take a look at the offerings from Scholastic Teachables. Include enough details, but not too many.
My more proficient writers tend to prefer this organizer because it gives them more room to expand upon their ideas. And you better make it interesting. Write about a time when you were the center of attention. Reading aloud and talking about the elements of narrative in what they read, teaches students about what components go into any narrative.
How did you help him or her? How did you feel when you opened the present? Write about a time when you taught someone else how to do something. Graphic organizers can provide the structure that students need to organize their narratives before they write.
Also, teach mini-lessons on strong introductions, endings, and adding details in the story. How do they change the plot? Write about the best vacation you ever took. How did you feel when you woke up?