Like the last writespiration, I thought the post would work just as well thinking about your antagonist.
What would happen if you actually met your main characters nemesis? Would you get on? Would you love them, or hate them? Would you sit in a bar and catch up like old friends? Are you so similar you would argue? Or would you be so intrigued to meet them you would have to drill them with 20 questions?
Take half an hour and write about what would happen if you met your antagonist, it might just help you get to know your character better!