Ever heard the phrase "Mary Sue," or it's male counter-part Gary Stu? No? Lucky you and I hope you never have to hear it directed to you. Enough with the weird rhyming, let's get to business.
A Mary Sue or Gary Stu is a character who is so perfect in their "originality" that they are completely unbelievable. They're super-talented in a variety of ways, gorgeous beyond words, kind, and with a tragic backstory they overcome, and every other character either loves them or wants to be them. They succeed at everything and get everything they want with little to no effort. They're also completely un-relatable to the reader, boring, and usually make my eyes roll out of my head.
Why is it important to know about them? Because you don't want to end up writing one. If you do then your readers plain and simply won't be invested in the story. How can you when your main character is so perfect you can't relate to their so-called problems?
As the writer, it's difficult to figure out if you've got a Sue/Stu on your hands. You have to take a step back and view all your characters as if you're not the one who wrote them which can be hard at best, insane at worst. What can help is making a brief list of your character's strengths, weaknesses, physical attributes, and personality.
If you're finding you've got way too many strengths compared to weaknesses or flaws then you're encroaching onto Sue/Stu territory. If everyone loves your character and thinks they're beautiful then you're starting to cross the line.
So, how to do you create a believable character?
Make them human. Every character should have flaws. They don't have to be obvious like a scar or missing limb and really, sometimes those aren't flaws depending on the situation. Mind you, personality flaws can be strengths depending on the situation as well. Let me break it down with an example (and a wee bit of "self-promotion"):
The character: Bane Grimgold from Avalora
His strengths: self-confidence, an uncanny ability to remember most of what he reads which enables him to make complex potions without needing to look in a book, Julliard level violin player, the ability to know pretty much everything when it comes to potions and Herbs, his general genius when it comes to language, history, and anything related to being a Dark Mage which he is. His ability to portal long distances and his wicked aim. He's an excellent cook and can clean.
His weaknesses: he has no sense of direction, he can't remember dates like birthdays or other significant events in his life which is why he gets a new ear-piercing for every important memory, unlike a normal Mage he can't do the basic spells everyone knows, he can't levitate his body or summon object to him which all Mages can do, and he's physically not powerful. He loses his self-confidence and "swagger" when he experiences strong emotions like confusion and depression. He also has a tendency to push people away when he's upset about something. He's lazy.
His strengths that can be weaknesses: he's stubborn to the point of being annoying occasionally, he's super-observant which means he can tell what's wrong with his close friends quickly which can bug the Hell out of them and make people unable to keep a secret around him, his motivation depends on the situation which hinders and helps the people around him, he hates certain aspects about his magic which to some people these aspects are a good concept, he has no internal sensor which is great most of the time but he has a lot of "foot in mouth" moments. He does have to be prodded to do any cleaning which means his room is normally a disaster zone.
Physical traits: he's over six feet tall and slender to the point he's too skinny. He's got dark hair which is perpetually messy, dark brown eyes, and pale skin. He has high cheek bones, a strong jaw line, and a long, thin nose. He also wears black all the time, normally lines his eyes, and has a ring on every finger.
All the above makes him seem more real, like you could walk into him on the street...I hope. Ha. Anyway, you probably noticed Bane has a lot of viable weaknesses, real concepts part of his personality he probably won't ever grow out of or change much. Sure he can play the violin and make any potion he wants but when it comes to magic everyone else can do he fails. He doesn't even have the ability to control an element which all Mages have at least one.
He'll always be the kind of person to go hide and shut others out when he's upset. He's not one to talk about his feelings or talk out a situation which has made him depressed or annoyed. In general, he's not good when it comes to talking about his emotions. All of this takes him out of the Sue/Stu category which means he can be related to by someone out there.
Does he have a tragic backstory? Sure. His dad died in a cave-in when he was fourteen and he's a half-Mage which means some people in the Mage community and the non-Mage community will never accept him and always hate him. He never made any friends until going to Avalora because all his school mates were non-Mages and the few Mages didn't want to associate with him because he had the potential to the Grim.
Is he a complex character? Yes. Which is what you want, especially when it comes to main characters. Minor characters don't have to be as complicated but it completely depends on their roles. The waitress we see for one or two scenes: we don't need something as complicated as above. We might not even need her name.
But, if you've got a main character then they need to be human, or at least come across as human. They need real feelings, opinions, flaws or weaknesses, strengths, and a personality. It'll make your story more believable and your readers will get attached.
Remember, if you fill out a similar chart and you notice you've got way more positive then negatives, you have to take a good look at that character to make sure they're not treading into Sue/Stu territory. That would be bad.
Until next time, you know what to do.