Well, Naruto is known for his positive energy. In this fanfiction, he could show his love for his siblings by bringing that positive energy into their lives. He would cheer them up when they are down, encourage them when they face difficulties. He might also cook for them or do some small but meaningful things, like helping them with their training or just listening to their problems.
One possible relationship is that of a mentor. Naruto, with all his skills and experiences, could be like a mentor to his siblings. He would teach them ninja techniques and how to face the challenges in the ninja world.
One popular storyline could be the siblings coming together to face a new, powerful enemy that threatens the Hidden Leaf Village. They might combine their unique skills, like Naruto's Rasengan and a sibling's special jutsu, to save the day.
In this fanfiction, Naruto would likely face many challenges. He'd have to provide for them, protect them from the village's possible discrimination, and also teach them ninjutsu. He might struggle to balance his own ninja duties with his new role as a caregiver.
Well, sometimes he's depicted as a fun-loving older brother. He'll play pranks with his siblings but also be there when they need him. His status as a hero in the village gives his siblings a sense of pride, and he uses that to boost their confidence. He might take them on adventures around the village, showing them all the secret spots he found when he was younger.
He might try to prove himself. Naruto has always been a determined character. So, he would likely focus on his training more, aiming to show his worth to those who neglect him. For example, he could strive to become a stronger ninja faster than his siblings, in the hope that his efforts would be noticed and the neglect would stop.
Often, they depict very close - knit relationships. The siblings are shown to be extremely loyal to one another. They might have each other's backs in battles, like in a fight against a group of rogue ninjas. One sibling could be in trouble, and the others would rush to save them without hesitation.
One reason could be that his siblings have some special abilities or talents that overshadow Naruto. In the ninja world, those with unique powers often get more attention. So, if his siblings possess something extraordinary, Naruto might be pushed to the side.
He would become more responsible. Naruto has always been a bit of a wild card, but with siblings to look after, he'd have to think twice before acting impulsively.
In some fanfictions, the siblings could be entirely new characters created by the author. They might have unique ninja abilities like one sibling could be a master of wind and water jutsus combined. Another could be a prodigy in genjutsu, stronger than Sasuke in that aspect. And the third might be a non - combatant sibling who is more into the political and diplomatic side of the ninja world, helping Naruto in a different way than fighting.