Who's Who in my new WIP?

Is Joslin the villain or heroine of my next novel? If heroine, then what do I do with Leonia? Joslin will force the story to end one way, Leonia allows it to end completely differently. I want Leonia's ending, but what if I want it with Joslin? What to do, what to do? Can this story ever work? (Just thinking out loud. Sorry!)