Formal:
* Protagonist: The main character.
* Antagonist: The character who opposes the protagonist.
* Figure: A person or being in the story.
* Personage: A person of importance or distinction in the story.
Informal:
* Person: A human being in the story.
* Being: A creature or entity in the story.
* Player: A participant in the events of the story.
* Individual: A single person in the story.
* Soul: A person's spirit or essence.
Figurative:
* Creation: A character made up by the author.
* Entity: A being with its own unique characteristics.
* Archetype: A character who embodies a universal pattern or type.
The best word to use will depend on the context of your writing. For example, if you are discussing the main character, "protagonist" would be a good choice. If you are talking about a minor character, "individual" or "being" might be more appropriate.