They could have adventures where they combine their skills. Naruto could use his ninja techniques like shadow clones, and Erza could use her different armors and magic. For example, they might fight against a powerful enemy that is a threat to both their worlds. Naruto's clones could distract the enemy while Erza changes into her strongest armor to deliver a powerful blow.
One adventure could be exploring different dimensions. Since Naruto is from his ninja world and Erza from Fairy Tail, they could use their combined knowledge and abilities to travel through various dimensions. They might encounter strange creatures and new forms of magic and jutsu along the way. And of course, they would be protecting each other as siblings should. Maybe they would find a way to bring peace to all the worlds they visit.
Naruto might gain the ability to use magic weapons like Erza. Since he's a quick learner, he could master the use of different magical swords or armors. He could infuse his chakra into these weapons to make them even more powerful. For instance, a sword that can cut through any material when combined with his chakra and also has the ability to cast magic spells.
They could start by meeting in a strange, in - between world. Naruto is intrigued by Erza's armor and Mirajane's different forms. They soon realize they have a common goal, which is to find a way back to their own worlds. As they journey, they share stories of their past adventures, with Naruto talking about his battles in the Hidden Leaf Village and Erza and Mirajane sharing tales from Fairy Tail.
One common theme is the idea of family. Since Naruto and Erza are in a brother - sister relationship in these fanfics, the concept of building a new family, loyalty, and protecting each other is often explored.
One way this could work is if there was a shared ancestry that was hidden or lost over time. Perhaps there was an ancient clan that had members in both the Naruto world and the Fairy Tail world. Through some convoluted plot device in the fanfic, Naruto and Erza could be discovered to be part of this long - forgotten clan, thus making them siblings.
Yes, there might be such fanfictions out there. Fanfiction writers often create crossovers between different anime universes, and the idea of Naruto being Erza's brother is an interesting and unique concept that some might explore in their stories.
It would probably be full of interesting interactions. Naruto's energetic and determined nature would contrast with Erza's more serious and disciplined personality. There could be scenes where Naruto protects Erza or teaches her some of his ninja skills.
One possible reason could be a misunderstanding. Erza might misunderstand Naruto's intentions. For instance, if Naruto is on a mission that involves some secretive actions, Erza could misinterpret them as something malicious and decide to betray him.
For Naruto, his development could focus on how he adapts to the magic - filled world of Fairy Tail. He might start to question his own ninja abilities and learn to incorporate magic into his fighting style. For example, he could learn to use chakra in new ways inspired by magic. Erza, on the other hand, could develop by learning about Naruto's strong sense of loyalty and how it differs from the loyalty within the guild. This could make her re - evaluate her relationships and her role in the guild.
She could influence his sense of loyalty. Erza is extremely loyal to her guild, and she would instill in Naruto an even deeper loyalty to his village and his friends. He might become more protective and dedicated to those he cares about. Also, Erza's own story of struggle and growth could inspire Naruto to keep pushing himself, even when things seem difficult.
Well, Naruto might bring his ninja skills to Erza's world. He could use his shadow clone jutsu to help Erza in battles. Maybe he'd be a bit of a troublemaker at first, not fully understanding the rules of Erza's guild. But over time, he'd grow to respect and adapt to it, using his unique abilities to support Erza and her friends.