Inner story

Often, if you're writing a long tale, you get to the point where you need to tell a story within the story.

You need to explain something that has happened in the past. You want to tell an allegory that helps foreshadow what's to come. You want to explain why someone has become the way they are.

There can be plenty of reasons to add a story in your story, and as many ways to tell it.

Have a character tell the story. Insert a flashback. Get lost in someone's thoughts.

There are a lot of ways to tell your inner story. Find the option with the most vibrant voice to keep your readers engaged in all layers of your story.