Kiba could also be a good match. If Naruto's sister has an affinity for animals like he does, they could bond over their love for their respective animal companions. They could train together, and their combined skills with their animal partners could make them a formidable duo in battles and missions.
One interesting 'Naruto has a sister fanfic' could be where his sister has a unique Kekkei Genkai that she has to keep hidden. For example, she might have the ability to control time on a very small scale, like freezing an opponent's movement for a split second in battle. This would add a whole new dynamic to the Naruto universe and the stories that could be told around it.
One possible plot could be that Naruto's little sister is also a ninja in training. She might struggle with the same kind of ostracism Naruto faced because of the Nine - Tails inside him. However, she could also be a source of great support for Naruto, helping him through his toughest times and together they could train to become stronger. Maybe she has a unique ninja ability that even Naruto is in awe of.
Well, perhaps the story could be about Naruto finding out he has a sister who was hidden away for her own safety. Maybe she has some unique powers that the villains are after, and Naruto has to protect her while also learning about his family's past.
She might feel guilty. Since they are siblings, she could be aware of Naruto's neglect and try to make it up to him in small ways, like sharing her food or secretly leaving him little gifts.
One interesting plotline could be how the twin sister affects Naruto's journey. Maybe she has a different view on the ninja world and helps Naruto see things from a new perspective. For example, she might be more in tune with the spiritual side of being a ninja and teach Naruto about ancient jutsu that he otherwise wouldn't have known.
The baby sister could change Naruto in some ways. He might become more responsible and less reckless. He would have to think about her well - being all the time. For example, he might not take on as many dangerous missions so that he can be around to protect her. And as she grows up, she could also inspire Naruto to strive for a better future for the Hidden Leaf Village, not just for himself but for her as well.
She could be involved in the Akatsuki plot in some way. In the fanfiction, she might have been sent on a mission that led her to cross paths with the Akatsuki members. This could create a whole new storyline where Naruto has to rescue his sister from the clutches of the Akatsuki, adding more depth to the Naruto universe.
In many fanfictions where Naruto discovers he has a sister, it often changes the entire dynamic of his story. It could give him a new sense of family and belonging that he lacked growing up. Maybe this sister was hidden away for some reason, like to protect her from Naruto's jinchuriki status bringing danger to her. This new relationship can also influence how Naruto approaches his ninja goals and his relationships with his friends.
The sister could also bring some new conflicts. For instance, if she has a different view on how the ninja world should be run compared to Naruto. This could lead to arguments and growth for both of them. Additionally, she might have her own set of friends or allies that Naruto has to get to know and work with, which would expand the cast of characters in the fanfiction and create more complex storylines.