Well, since it's called the'stronger little sister story', the little sister is surely one of the main characters. Maybe there's an antagonist, perhaps a bully or someone who challenges her strength. And there could be a mentor figure as well, someone who helps the little sister understand and develop her strength, like an old wise neighbor or a kind teacher.
The main character is the little sister, of course. But there could be other characters related to her story. For instance, she might have a best friend who witnesses her growth in strength. Or there could be a rival in a competition or a quest she undertakes. These characters would interact with the little sister and contribute to the development of the story.
There could be a mysterious old neighbor. This neighbor might have some knowledge about magic or strange phenomena. When the little sister shrinks, the neighbor could offer some clues or tools to help her return to her normal size. Maybe the neighbor has had a similar experience in the past and can guide the little sister through her ordeal.
The parents would be important characters. They could have different reactions. Maybe the father is more accepting and tries to teach the giantess little sister how to use her new power for good, while the mother is initially worried about how society will view their daughter. Their relationship with the little sister and how they deal with the situation can be a big part of the story.
Since I don't know the exact story, it's hard to say for sure. But presumably, the little sister would be one of the main characters. There might also be other family members like her parents or older siblings involved if it's a family - centric story.
Since I haven't read the novel, I can't tell who the main characters are.
The little sister was tired of being the smallest in the family. So, she started training like an athlete. Soon, she grew taller and stronger. In her story, she joined a local adventure club. There, she was able to use her height and strength to climb mountains and cross rivers more easily than others. Her fellow club members were amazed at how far she had come.
One possible story could be that the little sister was always shorter and weaker. But one day, she made a wish upon a star. The next morning, she woke up taller and stronger. She then used her newfound strength and height to help her friends in the neighborhood, like reaching high places to get a cat down from a tree or helping carry heavy things for the old lady next door.
Well, the little sister is the central character. Then there could be her parents who are initially clueless about what has happened to their daughter. There might also be a friendly neighbor kid who has a lot of knowledge about strange phenomena and joins in the quest to help the shrinking sister. And let's not forget the little sister's best friend from school who, when she finds out, comes over to offer moral support and some out - of - the - box ideas to solve the problem.
The obvious main characters would be the little sister herself. She could be a sweet and curious girl. And of course, her crush. He might be an older boy in the neighborhood, like a teenager who is kind and helpful. There could also be a villain, perhaps an evil wizard who caused the shrinking in the first place.
There could also be other characters like her friends or potential love interests. These characters would add more layers to the story. Her friends might support her in her adventures, while a love interest could introduce a romantic sub - plot, making the fanfiction more engaging.
Some fanfictions might introduce new characters as friends or allies of the little sister. For example, there could be a street - smart kid who helps the little sister understand the human world better since she's growing up in a rather unusual family. But the main focus always remains on the relationship between the turtles and their little sister.