My process of creating characters is very much unconscious, but they are usually one of the first ideas I have for a story's world. I'm conscious of someone being there, that I'm looking at this new paracosm through the eyes of someone specific, an individual. If you know about MBTI and cognitive functions, it has been said that for INFJs the creative process is often unconscious and that's why they feel almost like they aren't responsible for what they create.
Well, that happens to be exactly the case for me. I don't feel like I'm doing anything to create my characters. One day they just are there. It's like they already exist, they catch my interest. Some theme, or incident, or something made my mind wander where they already were and that's why I could find them.
It's almost like meeting a person in this reality. What I know first might be things like their name, their looks, the general air about them, their biggest obsession or how they treat other people. Something like that. To know more, I have to get to know them, either by perceiving, interacting, or listening them tell me.
Fictional characters are like that too. I have to write their story to get to know them in a level as deep as I desire to.
The characters are my window to their world and their story. While I learn about their world and story through their eyes, I also learn about them according to the world around them. When the story has been in my mind for a long time, I usually have a good idea about my character's reactions and opinions about things, but even so, to know what the character is going to do in a specific situation, I always have to write it. It's not uncommon for my character to make a completely different decision in their story, from what I thought they would, because I couldn't yet see all the variables that affected the character's decision in the specific scenario that I ended up writing.
So, as you can probably guess I'm one big discovery writer. I try to outline sometimes, with big projects, but I can't help it, it never turns out like the outline! It's just impossible to know exactly what the characters are going to do before the story actually gets there!
So, in short my characters seem to come to me out of nowhere, and they get fleshed out in writing only.
However, I'm not that unconscious of my internal processes anymore, that I would believe the characters actually come out of nowhere. I guess it would be more accurate to say that by brain synthesizes them from all the knowledge I have gathered about human mind, behavior, personality etc. Knowing this, I still feel like they are more than the sum of their parts.
I guess how I think that differs from some other styles of creating a character, is that I still don't consciously create them. I don't make lists of their interests or characteristics, or family backgrounds, I let those things come to me in the story. I don't plan their role in the story from beginning to end, I let that unfold before me. I also don't get my ideas from any specific source, like a person I know. I don't base the characters on anyone.
(Well, I have, a couple of times, when I was requested to do so, but even then, deep down, I never thought that the character was that person, just similar to them in some major aspects, so the character ended up being their own person anyway and having characteristics the inspiration didn't have and making decisions they never would have. I think it would be very hard for me the recreate someone entirely, because my mind just isn't wired that way. Fictional characters are as unique to me as "real" people.)
Even though there are no specific sources where my character would spring from, there definitely are specific thoughts or ideas that come to my head, and because I was thinking them, these characters specifically came to me, and not some other characters. Let's take an obvious example: I never would've written an explicitly asexual character if I hadn't discovered asexuality. That's pretty straightforward. But how I think the characters come to me, is a process of more subtle and smaller thoughts and ideas.
In the end, it's a web. It's impossible to say, whether the character is like this because the story needed them to be that way for me to be able to tell it, or if the story is that way, because the character couldn't have made any other choices because of who they are. Everything is connected to everything. It's a whole, more than the answer of a math equation. The character, and the story.
Sometimes, of course, I can pin point that "I probably ended up writing a character who had this trait because I had seen or heard this thing." But that's not the norm. Most often I couldn't tell which came first, the egg or the chicken. I think the human brain is capable of so much more than A-> B -> C kind of thinking. I think it's more often that all these things that are enough for the character to be a person, just come to me at the same time. Or that this thing and that thing that resonated with an outside thing were already in me, and they together resulted in a character, so it's impossible to say which one was the main reason, or there first, or the last nail.
Let's look at some characters.
This is Gemma. She only came to me in one sentence, one encounter with one of the main characters. She was not pleasant at all, and I wasn't that interested in her in the beginning, but then it became apparent to me why she acted the way she did and how her life story had led her to that point, and she became one of the dearest faces to me in that world.
This is Sierra. She started out as a sick girl I didn't really know because she spent most of the time sleeping. But when she got better she became an important part of the story, and her story is everything but finished, so I continue to learn new things about her personality.
These are Cherry and Forrest. I needed a detective who would be unable to solve the crime, and a detective who could, and these two came to me. Their individual strengths and weakness determined how the mystery unfolded.
This is Ririn. She's the character who was actually based on someone, but soon enough started to live her own life and oh my, did her and her friends adventures become a long story.
Derek is one of the characters that I can't say I like, but for some reason he insists on appearing in the story, over and over again. What can I do.
Hart is one of my most beloved characters. He's in a story with multiple viewpoint characters but he's sort of my default viewpoint, and I love looking at the other characters through his warm, fatherly, if often misguided eyes.
I guess what I'm saying is I discover characters in different points of the story and my initial thoughts about them may not always be right or fair to them. But I'll always get to know them more when I write more.
I love that they keep surprising me.