Hero Support: The Power of Side Characters

Do you ever find yourself enjoying a book mainly because you love the side characters? Supporting cast members in a novel are a wonderful way to flesh out a protagonist, giving them meaning and depth through a great friendship or alliance.
Think of Harry from Seeking Persephone. He serves as the comic relief, but he is also the reason readers can see the Duke of Kielder as an actual human being and someone who might just be worth caring for. If a side character like Harry can genuinely like Adam and show no fear of him, then maybe Persephone has a chance after all.
Or look at Harry Potter. Ron and Hermione were sometimes the only reasons I stuck with Harry during his prepubescent emotional roller coaster as he struggled to overcome his teenage angst and accept his destiny.
Side characters play an enormous role in storytelling. As authors, we must decide how many to include and how they can help build the foundation of the main character we are trying to portray.
In my Regency novel, A Rose for Braemore, my main character has a "man of all business" named Roberts. Think of him as a companion like Jacopo from The Count of Monte Cristo. Roberts is fiercely loyal, a voice of reason, and equipped with a sharp hint of sarcasm.
I had so much fun constructing and sprinkling his character throughout the manuscript. In all honesty, you could probably boil all of his interactions and dialogue down to about twenty-five pages total. Yet, he is such an integral part of this story.
That is the true power of side characters. They might play a supporting role on paper, but just like Genie in Aladdin, they have a funny way of stealing the entire show.