Well, in a fanfiction where Naruto joins ANBU, his training would intensify. He'd be trained by some of the toughest ANBU veterans. His skills in combat would become more refined as he'd learn to use weapons like kunai and shuriken with more precision. He may also develop new jutsu that are more suitable for covert operations. His growth as a ninja would be different from the regular path, focusing more on secrecy and assassination if required.
In this kind of fanfiction, one possible plot development could be Naruto having to deal with the secrecy aspect of ANBU. He might struggle with the morally grey missions they undertake. For example, he could be sent to spy on an old acquaintance. Naruto, being Naruto, might try to find a more positive solution to the situation rather than blindly following orders.
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.
In such a fanfiction, the plot could involve Naruto being constantly overlooked by the village. Fed up with this, he decides to join ANBU to prove his worth. He might face challenges like distrust from his ANBU comrades at first because of his reputation. But as he goes on missions, he shows his skills and determination, gradually earning their respect and changing their perception of him.
Well, one possible plot development could be Naruto joining the ANBU to seek revenge for Asuma's death. He might use the ANBU's resources and training to become stronger and hunt down those responsible.
One possible plot could be Naruto facing the internal politics of ANBU. He might struggle to adapt to their more secretive and sometimes morally gray operations compared to his usual straightforward ninja way. For example, he could be assigned to a mission where he has to spy on a former ally, creating an internal conflict within him.
One plot twist could be that the person who cheated on Naruto actually has a very good reason, like they were forced to do it to protect Naruto from a greater threat. Another could be that in ANBU, Naruto discovers that the cheating incident was part of a larger conspiracy against him. Maybe his new ANBU teammates turn out to be related to the cheater in some way, creating a lot of internal conflict for Naruto.
One possible plot development could be Naruto facing initial hostility in Iwa. Since he's from Konoha, the Iwa ninjas might be suspicious of him at first. But Naruto, with his determination and unique skills like the Rasengan, could gradually earn their respect. He might also learn new jutsu unique to Iwa and form new alliances, perhaps even finding a way to bridge the gap between Konoha and Iwa in the long run.
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.
One possible plot could be that Kurenai has some sort of influence on Naruto's decision. Maybe she sees his potential in a different way than others. She could encourage him to join ANBU to better protect the village and its people. Naruto, being influenced by her words and perhaps having a sense of admiration for her, decides to take on the challenge of joining ANBU.