Main characters, as we all know, are golden gods of absolute awesomeness, with sharp intellects, shiny biceps, and sparkling personalities that make fair folk of all genders faint out of sheer want"”both in and outside of the novel. Okay, that's not really true (we all know biceps can't really shine: they glisten). But even so, it can feel like it when we think about the huge amount of pressure that rests on the glistening deltoids of any main character: the direction of the action, the flavor of the narration, and most importantly, addiction of the readership. (No pressure.)
So, given all that (and how very much time you can spend on your main character as a result), it's amazing how some random, throwaway character, who was only supposed to have maybe ten seconds of fame--max--can suddenly steal all the spotlight and demand your readership's full attention (not to mention the author's). Somehow, what your imagination coughed up in a moment of thoughtless need ends up being more gripping than the most carefully crafted character, in whom you've invested every hope and expectation!
But what makes these seemingly accidents of ink, these minor--yet somehow spectacular--characters so enthralling? It has, I think, something to do with those very pressures and expectations that make a main character so important to begin with. Here are a few different reasons that side characters can outshine main characters, along with a few suggestions as to how your main character can get her sparkle back.
Mary Sues Always Lose
Remember all that pressure we talked about? It weighs a character down, and forces them into a tiny little box where their every personality trait is measured for its heroic quotient before being allowed out to play. And there's a good reason that! I mean think about it: generally speaking, no one wants a hero who is unlikable, foolish, incapable, or, worst of all, boring (unless, of course, it's a "thing"). So it follows that heroes tend to be likable, smart, and capable of extraordinary things--as well as anything else the author believes befitting of a hero.* For example, if an author admires those who can operate coolly and logically under pressure, then his main character will likely do the same.
Of course, all this pressure, constraining your character in all those ways, is almost a surefire way to make your main character dead boring. I mean, if your hero isn't going to get herself into trouble, then you're by definition leaving all of the most interesting parts to the side characters and villains (and getting into trouble is ever so much more fun--and more engaging--than getting out of trouble)!
Side characters, now--there isn't half as much pressure on them. And this leaves them remarkably free to be awesome. Which is perhaps why many of the most interesting (conceptually anyway) characters start out as side characters. So here's a trick: instead of treating your main character like the . . . well, main character, try treating them like a side character. And instead of trying to create a main character who can serve as a touchstone for ordinary in a sea of extraordinary, try to think of who the most interesting character would be, given the themes and scenes in your novel"”someone who would react in original and entertaining ways. You may be surprised how much more interesting a main character can be, when they don't have the weight of an entire novel (or more!) on their shoulders.
*Which, by and large, tend to fit in a fairly narrow box that you could set on your windowsill, and which the neighbor ladies and gents could pass by and murmur approvingly of what a well-mannered, appropriately heroic box it is.
That's Not a Character: That's a Camera!
Easily diagnosed by her habit of speaking entirely in questions, this main character is no Mary Sue. She's something decidedly different, and decidedly uncharacterlike to boot: a camera. And as a camera, she is perfectly suited to asking all the right questions and bumbling in all the right directions to best show off the author's beloved creations"”while remaining tragically"”epically--boring on her own.
You'll often find Camera Characters when you have a plot built around an awesome concept, some killer world building, and an amazing host of creatures and side characters that could really use some showing off. Unfortunately, with all the author's focus and interest on the world, concepts, and side characters (who, in this case, often serve as flavor for the world), they often end up forgetting one important thing: the main character.
So it's small wonder the side characters steal the spotlight, with their nifty concepts and interesting personalities! Especially in comparison to Mr. or Ms. Focused-on-the-Side-Characters. In this case, all you need to do is give your main character some of that good old fashioned TLC you gave all the rest of the cast and world. Spend some time thinking about their personality (like with a personality outline). Think about their inner and outer arcs"”both what they try to achieve in the world and what personal challanges they are trying to overcome. And, of course, the crooked path each arc takes. Once you know your character, it's far easier to figure out how they fit into your world.
Character Interaction Is King
If every person, animal, and majestic robot your character encounters invariably makes the determination that your hero really is the most speciallyiest and most extraordinariest sparklyiest snowflake that ever sparkled"”and any who fail to at minimum covertly worship the hero turn out to have a remarkable predilection to be proper bastards of questionable intelligence and absolutely no taste"”then you may want to reconsider your character interactions. Because while it is certainly wish-fulfillment for everyone to love your main character, it's anything but interesting.
Franklin D. Roosevelt once said, "I ask you to judge me by the enemies I have made." And this is vitally good advice for judging ones main characters. If character never does anything that draws rebuke, never loses arguments or friends, never makes enemies, and never does anything that could lead to regret, then that character is a born snoozer.
Characters are most interesting when they come into conflict and when they make mistakes"”which they correct in the least straightforward, most personality-packed manner. And they are often funniest when they have a slightly off way of looking at the world which causes them to do so. I mean think about the characters who really draw you in"”the ones who make you really want to read the next chapter. They are filled with social drama! And you can't have social drama without terrible misunderstandings, juicy conflicts of interest, and at the least, studly differences of opinion. So next time you find yourself worrying over whether your main character is main attraction material, remember to check the shine, let other (non-idiotic) characters hate your hero (and not because they're golden perfection on a plate), and let your character actually make mistakes and work to fix them, all on their lonesome. It may not be as pretty, but rooting for a hero who we want to succeed"”but worry about"”is far more interesting than watching a predetermined pony show.
Born Sidekicks vs. Burgeoning Heroes
Sometimes, the best main characters are actually culled from that always-greener field of incandescent side characters. Drizzt, for instance, famously started out as a side character. So if your side character continues to outshine your main character"”and steals every scene she's put into"”then you might want to put some thought into whether she needs her own story, and what that story would be. Perhaps she was the inspiration you were waiting for all along!
But, of course, that is not always the case. There are some characters who really do shine best from the sidelines. Characters whose main allure is their mystery, for instance, tend to do best winking from the shadows"”when pulled into the spotlight they can be decidedly less eye-catching. Characters with a dramatic but very short inner arc, or who are brilliantly reactive but not active, are other good examples of side characters who may be best served in their present roles. Now, that doesn't mean they're bad characters! It just means that you put them exactly where they need to be"”and that your main character needs to be strong enough to support such an awesome cast.