Yes, there might be such fanfiction out there. Fanfiction often explores unique and crossover concepts like this. Writers enjoy creating stories that combine different universes and characters, and the idea of Kagome from 'Inuyasha' being Naruto's sister in a fan - made story can lead to some really interesting plotlines.
One possible plot could be that Kagome, who has been living in her own world, suddenly finds out she has a connection to Naruto's world. As his sister, she travels to the ninja world. There, they both face a new threat that requires both of their unique abilities to overcome. Along the way, they learn more about their family history, and Kagome might introduce some of her own world's concepts to the ninja world, causing quite a stir. And of course, they'd have to deal with the reactions of their friends and allies in both worlds.
There could be. Fanfiction writers love to come up with unique and unexpected relationships. Since both Kagome and Sesshomaru are popular characters from the 'Inuyasha' series, some writers might have decided to write stories where Kagome is Sesshomaru's sister to explore different plot possibilities, such as how it would change their interactions with other characters or the overall story arc.
One common theme is family. Since she is Kagome's sister, the story often explores their sisterly bond and how it affects the plot. For example, the sister might be very protective of Kagome.
Common themes could include the exploration of their shared heritage. If Kagome is Sesshomaru's sister, they would likely have some sort of shared past or origin that could be delved into. There might also be themes related to their different upbringings. Kagome was raised in a human village while Sesshomaru in the demon world, so how these different upbringings shape their personalities and how they interact with each other as siblings could be a major theme. Additionally, the theme of protecting each other from threats that target their family due to their unique relationship could also be present.
In the Naruto world, Kagome would bring her knowledge of sacred jewels and purification. This could be useful in dealing with cursed objects or dark chakra. She may also encounter difficulties in adapting to the ninja culture which is different from her own feudal Japan. However, her determination would likely drive her to learn and contribute to the Naruto world in her own way.
When Kagome meets Hinata, she could see Hinata's shyness and determination to become stronger. Kagome would probably encourage her. And with Sakura, they could have an interesting relationship. Kagome might teach Sakura some new ways of using energy for healing, while Sakura could show Kagome the more scientific aspects of the ninja medical field. Also, Kagome would be curious about the various jutsus that all the characters possess and would likely ask a lot of questions.
In the Naruto series, Naruto doesn't have a biological sister in the original story. So in this fanfiction, the author probably creates a new character to be his sister. It could be an original character with unique abilities and a complex backstory that leads to the situation where Naruto dies by her hand.
Well, a really engaging kagome's little sister fanfiction could be the one where she gets transported to a different era than Kagome. In this new setting, she has to adapt and find her own place. She might meet new characters and face different challenges that are unique to her, which makes for a great read as it gives a fresh perspective on the whole Inuyasha - related world.
She could be an original character created specifically for this fanfiction. The author might give her unique abilities and a distinct personality to make the story more interesting.