The main character is no doubt the little pianist. However, there could be other important characters. There might be an old musician in the neighborhood who has a lot of wisdom about the piano and gives the little pianist some valuable advice. Also, there could be friends of the little pianist who either encourage or discourage the pursuit of piano playing depending on their own views on music.
Naruto is the central character as per the title. There might also be some original characters created by the fanfiction author. These could be people who are drawn to Naruto's piano playing, perhaps in a creepy or obsessive way. Or they could be other pianists in the Naruto universe who are either jealous of Naruto's skills or are aware of the dark secrets behind his music.
The 'the little pianist story' could potentially be about a child prodigy pianist. This little pianist might be born into a musical family or might have a natural aptitude for music. They start their piano journey at a very young age, quickly mastering basic skills. They might participate in local competitions and gradually gain recognition in the wider musical community. Along the way, they could form deep friendships with other musicians or experience the joys and sorrows of musical performances.
I don't have enough details about 'the little story' to say for sure, but it could be a child, a pet, or an old wise man.
In the chicken little characters story, the key character is Chicken Little, the one who believes the sky is falling. Another important character is Foxy Loxy, a rather sly animal. There are also other barnyard animals like Henny Penny and Ducky Lucky who are involved in Chicken Little's adventure when he spreads the word about the sky falling.
The main characters of 'little busters main story' are the boys and girls who form the Little Busters. Riki Naoe is a central character, being somewhat of a narrator in a way as we see the story through his perspective at times. Kyousuke Natsume is a charismatic figure in the group. Then there are other members like Masato Inohara and Kengo Miyazato. The female characters such as Rin Natsume also play significant roles in the story, adding different dimensions to the relationships and the overall plot.
The main characters are Little Fred and Little Buck, of course.
Not having read the 'little by little 5th grade story', it's hard to say exactly who the main characters are. However, in a typical 5th grade - centered story, we might expect to see a young protagonist, perhaps a boy or a girl who is dealing with the typical issues of 5th graders like homework, friendships, and getting along with parents. There could also be side characters like the school bully, the kind librarian, or the strict principal that play important roles in the story's development. But again, this is just a general idea based on what we might expect from a 5th grade story.
The story mainly features Little Blue and Little Yellow. They are the central figures around which the whole story revolves. Their interactions, like playing together and hugging, drive the plot forward.
The main characters are Little Blue and Little Yellow. They are the ones who go through various experiences in the story like playing together and getting all mixed up.