In some fanfictions, the little sister's friends at Hogwarts could be popular characters. They could be from different houses and have different personalities. For instance, a Gryffindor friend who encourages her to be brave and stand up for what's right, or a Ravenclaw friend who helps her solve the mysteries surrounding her brother.
Obviously, Sherlock himself is a very popular character. His brilliant mind and unique personality are central to the fanfiction. The little sister, of course, is also a key figure. Depending on how she's written, she can be a strong, intelligent character in her own right.
Sakura can also be a popular character in these fanfictions. She might be a friend to Sasuke's sister, or there could be some sort of rivalry or cooperation between them. Also, characters from other ninja clans might be involved, like Shikamaru. His intelligence could be used to help Sasuke's sister in strategic situations in the story.
A really interesting 'Regulus little sister fanfiction' might involve time - travel. Maybe she travels back in time and tries to prevent her brother from getting involved with the Dark Arts in the first place. She could meet young versions of other important characters like Sirius and James, and her interactions with them could change the course of the future.
Some fanfictions might introduce new characters that become popular. For instance, a new vampire who befriends the little sister. This vampire could have a different set of powers or a unique backstory that makes them stand out. Also, other members of the Cullen family, like Alice, could have a closer relationship with the little sister in the fanfiction, which makes her a popular character in this new narrative.
Well, obviously the little sister herself is a very important character. Depending on how she's written, she could be really kind - like a Hufflepuff at heart - or really brave and adventurous like a Gryffindor. Then there are the classic characters from the original series that often play a big role. Hermione would likely be there to offer her wisdom and help the little sister with her studies. Ron would be the comical friend, always getting into some sort of trouble but also being very loyal.
Sansa Stark is a very popular character in 'Game of Thrones' sister fanfiction. Her journey from a naive girl to a politically astute woman offers a lot of room for fanfiction writers to explore. Arya Stark is also popular. Her skills as an assassin and her independent spirit make for exciting storylines. Another one could be Cersei Lannister. Even though she is a complex and often - hated character, her power - hungry nature and her relationships with other characters can be the basis for many interesting fanfictions.
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.
One of the well - written little sister characters might be those who are depicted as a blend of innocence and curiosity. For example, a character who is constantly asking questions about Rick's inventions and Morty's adventures, which makes her endearing. Another could be a little sister who has a strong sense of justice. She sees the wrongdoings in the crazy world they live in and tries to set things right in her own way.
Debra - Jo is often a popular character. She has a strong personality and her friendships and rivalries can be explored in fanfiction. Writers might create stories about her new hobbies or how she overcomes challenges.