This category of Storytelling Elements is exactly what it looks like - it's the characters in your story. The players on your stage. The puppets on your string- I mean the people in your world. :)
Without these personalities on the page or on the screen, your story would be rather boring, but before you can write one line of dialogue or construct a single decision tree, you need to know who's saying those words or making those decisions. This will affect the rest of the story, because heaven knows we've all had that experience where you planned for C to come after B which follows A, but your characters skip A, detour around B, and arrive at C in a stolen shuttle with a cargo of illegal medicine.
You've all had that experience too, right?
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