Maybe they both have a common enemy that forces them to team up and during their journey, they start to feel a strong bond that makes them suspect they might be related. They could then start to explore their pasts and find out that they have the same father or mother who was involved in some sort of cross - dimensional love story.
Another plot could be that they are reincarnations of ancient brothers who were heroes in a long - forgotten time. They start having dreams about their past lives and gradually piece together that they are brothers. As they accept this fact, they combine their powers, Ichigo's Soul Reaper and Hollow powers with Naruto's ninja skills and chakra, to fight against a new threat that is emerging in both their worlds.
One idea could be that Ichigo and Naruto are brought together by some sort of interdimensional rift. They initially don't understand each other's powers but soon realize they share a common goal of protecting their friends and worlds. They could team up to fight a powerful enemy that threatens both their universes.
Perhaps in the fanfiction, as brothers, they have to face a common enemy that is specifically targeting their family line. This would make them rely on each other's unique abilities. Naruto's never - give - up attitude combined with Neji's precision could lead to some epic battles.
Well, a great plot could be that Kakashi, being Naruto's brother, decides to train Naruto in some super - secret jutsu that only their family knew. This would give Naruto an edge in battles and also strengthen their bond. Or perhaps they get into an argument over their different views on the village's future, but in the end, their brotherly love prevails. It could also be interesting if they both have to protect a precious family heirloom from villains who want to use it for evil.
One idea could be that Ichigo and Naruto are transported to a strange new dimension where they have to work together to find their way back home. They start by comparing their skills and learning from each other. For example, Naruto could teach Ichigo some of his shadow clone techniques, while Ichigo shows Naruto how to use his zanpakuto more effectively.
Maybe in the fanfiction, Ichigo and Naruto meet during a tournament held in a world that combines the elements of their respective universes. They start as rivals but soon realize they have more in common and end up fighting together against those who want to disrupt the tournament for their own evil purposes. This could involve them combining their unique powers like Ichigo's Getsuga Tensho and Naruto's Rasengan in creative ways.
One idea could be a story where Naruto and the Lee brothers team up for a special mission. They could face a powerful enemy that requires their combined skills. Naruto's jutsus and the Lee brothers' taijutsu would make for an exciting battle sequence.
One idea could be that they discover they are brothers in a hidden past plot twist. Maybe their parents were from different villages but fell in love secretly. As brothers, they could team up to face a new and powerful enemy that neither could defeat alone.
A possible fanfiction plot could involve Naruto and Sai being brothers in a parallel universe. In this universe, they are both part of a special shinobi team from the start. Sai's artistic abilities combined with Naruto's determination make them an unbeatable duo. They face challenges together, like protecting their village from a new and powerful threat, all while exploring their newfound brotherly relationship.
Well, their relationship could be really interesting. Since Naruto is so full of energy and determination from the Naruto series, and Ichigo is brave and strong - willed from Bleach. As brothers, they might constantly compete with each other in terms of strength and skills. They would also be very protective of each other. Naruto's rasengan and Ichigo's Getsuga Tensho could be used in combined attacks during battles against powerful enemies.
One idea could be a crossover where Ichigo and Naruto are transported to a strange new world together. They have to combine their skills, like Ichigo's Zanpakuto abilities and Naruto's ninjutsu, to find a way back home.