Having a hundred characters in a story will be complex to keep track of. When writing I like to think of 20 or so main characters that will be part of the plot, most of the time I havemore than 20, but during my writing phase, I take note of the characters, if there are similar characters in personality I combine them,
Think of the characters like twins in the womb, the stronger one will absorb the weaker. Condensing the lines to one character will make that support offered more meaningful instead of squandering one off lines on someone unimportant.
Support characters should have their own unique personalities and like the main cast, back stories should be drawn up. Also creating these back stories, will clarify the supports relationship to the plot. Support characters can offer your story a lot, comic relief, is type savior complex that is exchanged, in fact support characters are often early saviors of the leads. Offering shelter, training or supplies along with helpful advice will enrich the storyline.
Comic relief was mentioned earlier, and it really does help regulate the emotions of the reader. Heavy topics are hard for some to read, other times hard to hear news is given, it is helpful to give them some way to chuckle, it produces two immediate results. Allows them to take information on the chin, and it helps them to turn the page. There are other benefits to comic relief to be explained in future articles, just know for know that it should flow in the dialogue nothing worse than an uncomfortable attempt at a catch phrase.
As a rule of thumb, the smaller cast your story employs will result in more complex relationships and personalities. With less characters to keep track of, the writer is able to narrow the focus. Using the story Stand by Me is an example to my point. It has a small cast under twenty characters. The focus is on the boys, their interests, their moods and how they grow out of childhood and are entering into a changing and shrinking world.
Sidekicks and support are similar but different, support isn’t always a main character but should still prove integral to the plot, remember if they have no purpose to be in the story why mention them. So, make them have a piece to a riddle to solve, or possess a clue to the next part of the plot. In contrast a side kick if there is a protagonist on a journey will inflate the leads ego, will help them. A support character shouldn’t care if the hero succeeds or fails, but their input is invaluable to the hero thus making it a suspenseful and purposeful interaction.
I hope this helps, I find that support characters can strength a plot and can naturally help the progression from scene to scene. Please check back soon for my articles.