Fan Casting Four-Temperament Ensemble in Sort by Tropes

There are many ways to make a group of people diverse without giving them overly specialized roles within an ensemble. One way is through matching personality types according to an ancient proto-psychological theory. The Four Temperaments (also called the "four humors") was a theory that behavior was caused by concentrations of body fluids. Though this has been a theory long-since discredited from a scientific standpoint, the general idea still remains and the theory is still used for personality profiling. An ensemble based on these four humors can make the cast diverse without actually changing the roles of the characters in the story.