So there's a malevolent empire threatening to take over the world, and only a small pocket of resistance must combat it by any means necessary. However, each of the resistance-troops have their own backstories relating to why they're fighting said empire, as well as internal-conflicts that mostly relate to deciding between succumbing to their pasts, or leaving them behind for the present. So now, they must fight two conflicts: The malevolent empire (the plot), and their own pasts (the characters). Here's what the story can be like, based on what it's focusing on: