Well, their brotherly relationship could also be shown in how they deal with the village's problems together. Naruto's strong will and Minato's wisdom could combine. They might face off against a new, powerful enemy that threatens Konoha. Naruto would be all about charging in, while Minato would plan a more strategic approach, and they'd have to learn to work with each other's styles.
One way to explore their relationship is through family memories. Since they are brothers in this fanfiction, they could have some shared family experiences that Naruto never had in the original story. Maybe they had a special place in the village where they used to play as kids, and as they grow older, they go back there to reminisce and strengthen their bond.
Their relationship can be explored through flashbacks. For example, Minato could have left behind memories or messages for toddler Naruto that are revealed as Naruto grows. Another way is to have Minato's spirit interact with toddler Naruto, like guiding him in his dreams. They could also explore their relationship by showing how Minato's traits are already starting to show in toddler Naruto, such as his determination.
One way to explore their relationship is to have Minato's friends, like Jiraiya, tell baby Naruto stories about his father. As Naruto listens, he starts to form an image of Minato in his mind. This could lead to Naruto trying to imitate Minato in different ways. Also, the fanfic could show how Minato's sacrifice for the village is slowly understood by baby Naruto as he grows up, deepening the emotional connection between them.
Their relationships could be explored through flashbacks. For instance, we could see how Minato interacted with Tsunade when he was alive. Maybe he sought her advice on certain matters, or they had some joint missions. This would give us insights into their respect for each other.
One way to explore their relationship is through flashbacks. For example, showing their childhood together, how they were different even as kids. Batman might have been the more serious and rule - abiding one, while Joker was always the troublemaker. In the present of the fanfiction, Batman could be trying to rehabilitate Joker, believing that there is still some good in him because of their brotherly bond.
Their relationship would likely become more equal. In the original story, Minato was more of a distant, heroic figure to Naruto. But through time travel, they can interact as peers, sharing knowledge and experiences. This would deepen their bond.
In a fanfiction about them as siblings, their powers could be an interesting aspect. Naruto has the Nine - Tails' power, while Tayuya has her music - based jutsu. They could train together and combine their powers in unique ways. For example, Naruto could use his chakra to enhance Tayuya's sound - based attacks, creating a powerful new form of combat that is exclusive to their sibling bond.
In fanfiction, Naruto and Obito could have a very complex relationship as brothers. Obito, with his troubled past, could be both a source of protection and a cause for worry for Naruto. Naruto's positive nature might initially be at odds with Obito's more jaded view, but over time, Naruto could help Obito see the good in the world again.
If they were brothers, they would probably have a very competitive relationship at first. Naruto is always trying to prove himself in the ninja world, and Natsu is constantly looking to be the strongest wizard. But over time, they would realize that together they are much stronger. Their different abilities would complement each other. For example, Naruto's wind - style jutsu could enhance Natsu's fire magic, making it even more powerful.
The emotional bond would be stronger. Naruto wouldn't have to face the pain of growing up without a father. Minato could be there to cheer him on during his training and be a source of comfort when Naruto faced difficulties, like when he was bullied as a child. He could also help Naruto better control the Nine - Tails' power from the start.
Another aspect could be a time - travel fanfiction. Naruto gets sent back in time and meets a young Minato. They train together, and Naruto shares some of his future knowledge in a veiled way. This could lead to a different development of Minato's skills and a unique bond between them.