In the fanfiction, Naruto could be sneaking into ANBU to prove himself. He might think that if he can infiltrate this elite group, he'll be seen as a true ninja. Once inside, he could encounter some old friends or foes who are also part of ANBU. He'll have to use his wits and skills to avoid getting in trouble. He could also discover some new jutsu or training methods that the ANBU use, which could help him in his future battles.
One possibility is that Naruto's skills would be put to extreme use in ANBU's more secretive and dangerous missions. His unique abilities like the Shadow Clone Jutsu could be utilized in stealth and assassination operations, but he might also face a moral dilemma as ANBU often deals with morally grey areas.
He could become a more solitary and brooding character. In the ANBU, Naruto might use his pain as fuel for his missions. He could start to distance himself from his old friends, as the nature of ANBU work is often secretive and isolating.
He could be motivated by curiosity. Naruto is always eager to learn new things and the ANBU is a mysterious organization. He might want to know what goes on in there.
One possibility is that Naruto struggles to balance his new Anbu duties with his feelings for Sakura. He might start to distance himself from her as the Anbu work takes over his life.
Well, Naruto going to Anbu in fanfiction could mean a whole new set of character developments. He might struggle with the secrecy and lack of recognition that comes with Anbu work. His relationships with his friends could also be strained as he has to keep his Anbu activities under wraps. And he'd probably meet some really tough opponents that test his limits in ways he hasn't experienced before.
In some fanfictions, Naruto might be searching for some crucial information about the Uchiha clan. He could stumble upon Itachi's personal diary and learn about his true motives and the secrets he's been keeping from everyone.
In this fanfiction, Naruto might use his shadow clones to create chaos at the Anbu headquarters. He could make it seem like there are intruders everywhere, causing the Anbu to go on high alert and run around in confusion. Maybe he'll also replace some important documents with funny pictures or put whoopee cushions on their chairs.
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.
Well, he might introduce some unique ninja skills to Hogwarts. Maybe he'd show the students how to move stealthily like in the ANBU, which could be a new concept for them. And his combat skills could be a shock to the wizards used to magic duels.
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.