They could go on an adventure to find a powerful treasure that combines the power of the One Piece and some kind of ninja - related artifact. Maybe they'd have to fight against a new enemy that is a combination of pirates and rogue ninjas. They might travel to new islands where Naruto's ninjutsu would be useful for exploring hidden caves, and Luffy's stretching ability would help them reach high places or cross large gaps.
Common themes in 'naruto luffy brother fanfiction' include power - sharing. Given their unique abilities, fans like to write about how they would teach each other or combine their powers. Also, friendship is a big theme. Even though they are brothers in these stories, their relationships with other characters from their respective worlds are still important, and the fanfictions often explore how they maintain those friendships while being brothers. And of course, there's the theme of family. The idea of them being brothers brings in a whole new family dynamic that wasn't present in the original stories.
Well, there is some 'naruto luffy brother fanfiction'. Some of them explore how their different powers would interact if they were brothers. For example, Naruto's ninjutsu and Luffy's Devil Fruit abilities could make for some really exciting adventures together. Also, the different worlds they come from, the Hidden Leaf Village and the Grand Line, could be combined in creative ways in these fanfictions.
Naruto might give Luffy training in stealth. Since Naruto is a ninja, he is well - versed in moving around unnoticed. Luffy, on the other hand, is more of a straightforward fighter. So Naruto could show him how to approach enemies without being detected first, which would be a new and useful skill for Luffy in his pirate adventures.
Naruto might also be determined to change his brother's mind. He would keep showing his good side, like his kindness and his strong will to protect the village. He could think that by being a better person, his brother will eventually stop hating him. He may even go through some tough training to prove himself not only to his brother but also to the whole village. And in the process, he may face a lot of difficulties and rejections from his brother, but he won't give up easily.
Sasuke would be furious. He already has a strong sense of justice and loyalty to Naruto. He'd likely immediately start looking for Naruto, using his Sharingan to track any possible leads. He might even go against the village rules if he thought the village was involved in Naruto's kidnapping.
Sakura might be really surprised at first. She could offer to help Naruto with his girl disguise, teaching him things like how to do his hair or choose the right clothes. She might also find it a bit funny but would be supportive in the end, seeing it as part of a mission. Sasuke, on the other hand, might be a bit more aloof. He would probably just raise an eyebrow at Naruto's new look but wouldn't make a big fuss about it as long as it was for a good reason.
His friends would be shocked at first. Sasuke might feel a sense of responsibility to find Naruto and bring him back. Sakura would probably feel guilty, especially if she was somehow involved in the situation that led to Naruto being cheated on.
There might also be a sense of self - doubt. Naruto may start to question his own judgment. He thought his friends were true to him, so the betrayal could make him wonder if he was wrong about them all along. He might also doubt his own worthiness as a friend and leader, which could have a long - term impact on his self - esteem.
Sakura would be worried sick. She might immediately inform Kakashi sensei and the rest of the village. Then, she would probably want to be part of the rescue mission. Sakura has grown stronger over time and would use her medical ninjutsu and combat skills to help save Naruto. She would also be constantly worried about Naruto's well - being and would encourage the others to move faster.