One of my characters pretty much moves every plot element and other character in the story. But she's not the 'real' active main character with all the screentime so to speak. That role goes to the other characters that she drives. So turns out the one character that i barely show is the most important one in every way. And story-wise she's just not there, not able to do anything that deserves exposition in a meaningful way. This is very vague, sorry but compare it to Neuromancer if you read it. The main chars are constantly on the forefront, actively doing, but in the end you figure out who's really been pulling the strings of the story and was there all along. I don't need a 'big reveal' per sé but that's the sort of character i'm talking about. For a character to be as valid and important as a main character, is it enough if she mostly shows her activity through the other characters actions or is it impossible to compete for the main spot (the one the reader cares about) if other characters get all the screentime?
Are you going for a character like Samwise Gamgee of LOTR? Not the main character but Frodo would never have got that far without him and Sam was arguably the true hero. Otherwise, what you said reminded me of Zootopia a little. Originally, Nick the Fox was the main character, not Judy. They realised the bunny Judy was stealing the show at every turn and finally saw that the story is about Judy and they had to redo the whole thing. But the story's far better for it. So you have to ask: perhaps are you telling the right character's story? Is your current main character really the best person to tell the story you wanna tell?
Maybe this other character should be your focus character? Or maybe it's simply a lack of goal, characters often become reactive when they have no goal to actively pursue all the time.
I think that depends on what you mean by "important." Someone can be central to the plot without getting a lot of focus. A master manipulator rarely gets a lot of screentime because it's typically more interesting watching the effects of their handiwork rather than them sitting around pulling strings.
I had the same problem like a week ago. I'm 430 pages into my story and I realize the main character is not the main character. although I have several main characters the protagonist totally faded away and his brother stole the story. at that point I was debating on just changing the protagonist or not but because of the storyline I didn't want to. So what I did was went back to the beginning to find out where it all went wrong. I added about 3 or 4 more chapters around the beginning for the protagonist and that made all of the differene. Not only did it flesh him out a lot more it also brought out his goals and personality in a way that integrated into the later chapters. I'm bad these things I'm not sure of a better way to describe it.... But basically I didn't know enough about him. Adding those chapters helped me get to know him, thus helping me bring him to the front in the later chapters also.
Are you talking about Harry Potter? You know, that character that is supposed to be so important but would've died like, six times if not for somebody saving his butt? I mean, really let's face it, Harry sucked at magic, he sucked at potions, he sucked at herbology. If not for everybody literally doing everything for him, and giving all kinds of cool stuff, he wouldn't have had a prayer. Incidentally, I'm kind of in the same boat. I started out with a young girl as the main character of my book, but as I've progressed, she's been more of a bit character that's merely observing the things going on around her. I want her to grow into her own as the story progresses, but for the moment I've been focusing almost all of my attention on a single "supporting" character.
In both Tolkein's "Lord of the Rings" and Rowling's "Harry Potter", the entire plots, and therefore movements of the main characters, pivoted on characters that were not seen until the end (Sauron and Voldemort, respectively).