Monthly Obscure Trope Series — Cast Calculus

So, how does a writer figure out what characters they should put in a story? We’re not talking powers necessarily here—we’re talking about personalities.  

The answer depends on how many main characters there are in a story. 

Don’t worry about villains or side characters. Just main characters—just the ones that are central protagonists. 

And don’t worry if you weren’t any good at math in school, because Cast Calculus doesn’t involve any actual math. Not really. 

I’m going to teach yo...