Screenwriting : Character arcs on minor/supporting characters? by Mark William Chambers

I know I am about to be called all sorts of fool and amateur, but not even main characters need to change. Look at Captain America, he is the same guy at the start and end of all his stories, especially Winter Soldier. The world changes around him. There must be change for the story to progress and reach an end. The change is what we are witnessing. Now to get to your question. Does your story need a secondary character to change. Die Hard did, the desk riding cop "Al" that couldn't bring himself to shot. Shots the bad guy to save John. Pirates of the Caribbean everyone changes in that. They may have desired the change from the first act, but everyone changes. Write what you want, if your story needs it. Delete it later, it is easier than having to shoe horn it in later.

Your minor and supporting characters, your sub-plot(s), so to speak, should reflect your theme, either in support or denial, imo. They may, or may not have a shift of sorts, but they must have a reason to be there, in your story. Focus on your "A" story first, then layer in the sub-plots, if needed. They are not always necessary. And I believe your lead character must grow and change. He/she must have an arc, in that he/she is different at the end of the script. To take that further, I would suggest that every scene is a mini-movie, with its own three (or more) act sequence, with the main character (or the character in which the scene is about) having his/her arc, either up or down, but a change in some way. I have never seen Captain America, so I can't speak to that.

No, like Jan stated, Supporting characters should pay homage more to the theme of your story" than to character development. It's enough these days just to focus on developing your leads... let alone your support characters.

Thank you for the input guys. I'm hoping to implement a strong supporting cast but I'm trying to derive from any subplots over taking the central story. I've had issues in the past with subtle subplots and I want to make sure this does not happen in my first draft (actually a rewrite) but on the same characters but with a much more powerful theme.

@Ellis you're correct in what you say. But they are environmental changes, not actually changes to Capt. He is still ridged in his belief. He does not compromise his values to get to a solution quicker. I think having such a rigid and unchanging character means you can treat him like a bomb. Everyone knows exactly what to expect, just set him in different scenarios. The world tends to change around him. That was in issue in Man of Steel. Superman is not suppose to kill. So now that we have crossed that line, does that mean Superman is free to kill? I am a strong believer in making characters change. I may even go as far as making act against something they will be forced to do themselves later on in the story. I like watching them try to morally neutralise their actions.