His relationship with his former teammates becomes strained at first. They might feel betrayed or confused as Naruto suddenly leaves the team. Sasuke, for example, could see it as Naruto abandoning their rivalry and their unspoken bond within Team 7. Sakura might be sad and miss Naruto's presence, especially his positive energy. However, over time, they could come to understand his reasons and gradually rebuild a different kind of relationship, one that is more based on mutual respect from a distance.
Naruto faces a whole new set of challenges. Firstly, the ANBU has a strict code of conduct which he needs to adapt to. The missions are often solo or with very small teams, so he has to rely more on himself rather than his comrades like in Team 7. Also, the enemies he faces in ANBU are often more powerful and cunning. He has to keep his identity a secret, which is a big change from his more open - natured role in Team 7.
Well, one major plot change could be in the power dynamics. Since Naruto in Anbu is likely more skilled and experienced. He might take a more dominant role in Team 7's missions. For example, he could quickly assess and handle dangerous situations that the original Team 7 might struggle with. This could also change the relationships within the team. Sasuke might be more competitive towards Naruto, seeing him as an even greater rival. And Sakura might have more admiration or fear towards Naruto because of his Anbu status.
Well, his relationship would become quite strained. Sasuke might feel betrayed as Naruto was an important part of their dynamic. Sakura would be confused and sad. She had come to rely on Naruto in many ways. Kakashi, as the sensei, would probably feel like he failed Naruto in some way. Naruto's departure would leave a big gap in the team, and there would be a lot of unspoken emotions.
In some fanfictions, Naruto might join Anbu because of Sakura to prove himself worthy of her. Maybe he thinks that by becoming an elite Anbu member, he can show her that he's strong and reliable.
Naruto's personality might become more reserved initially. The Anbu experience often makes ninjas keep their emotions in check. So, he might not be as boisterous as the original Naruto. For Sasuke, he could be more on edge around Naruto. He would sense the change in Naruto and feel pressured to keep up. Sakura might become more cautious too. She would see the more serious side of Naruto and might try to be more like him in terms of being focused during missions.
In some fanfictions, Naruto might leave the Anbu due to internal conflicts within the organization. There could be corruption or power struggles. Naruto, being the idealistic character he is, would not want to be part of such a messed - up system. He might have discovered some dark secrets about the Anbu that made him decide it was not the place for him.
Well, in such a fanfiction, perhaps Naruto has just lost Sasuke again and is deeply depressed. The ANBU, seeing his skills and his need for a distraction, recruit him. He starts off being a bit of a misfit in ANBU, not following all the rules because of his independent nature. But as he continues, he starts to understand the importance of their work. He might even form new bonds with his ANBU comrades, which slowly help him come out of his depression.
Well, Naruto might face a whole new set of challenges. In the ANBU, he could be pushed to his limits physically and mentally. Maybe he'd use his unique skills in stealthier ways compared to his normal fighting style. Also, his relationships with other ANBU members would be interesting to explore, as he's a bit of an outlier with his loud and brash personality.
In this kind of fanfiction, Naruto might face some really tough and secretive missions in ANBU. He could be trained in new and deadly ninja techniques. Maybe he would also form some unexpected alliances with other ANBU members, learning from their different skills and experiences.