How to merge character into theme?
Give the reader a sense of the character and connect this to your thematic question.
First you need to understand that a character is the sum of his/her actions. To get a sense of character we need to see how he/she behaves during a difficult dilemma/decision.
The way this character acts when facing a difficult decision will give us a sense of who this person really is.
Meet Stewart (39) a jobless bank accountant whose only child is suffering from leukemia. He can be the donor, but he cannot afford the treatment. Therefore he decides to rob a bank. He is familiar with a particular bank he used to work for and got laid off because he called in sick to many times to take care of his child as a single parent.
So in the midst of the robbery his former boss has a heart attack. Now here’s the dilemma: Does Stewart help his former boss and risk to be arrested, or does he decide to take the money to make sure his kid stays alive.
So the way Stewart goes about this dilemma, tells us a hell of a lot about his character. Does he help his former boss? Does he decide to let him die to save the kid?
Now this scenario not only tells us something about the character, it can also be used to explore the theme of the movie to a great extent. So for instance, if the thematic question of the movie would be: „Is it ok to sacrifice others to save your own flesh and blood?“, than the scene, I described above, not only reveals character, it also introduces us to the overall thematic question(s) that the movie will explore.
What’s the takeaway of all of this?
Create dilemmas that not only force the characters to act and thereby give us a sense of character, but also choose these dilemmas wisely to illustrate the overall theme of the movie.