He would be highly skilled in combat from a young age. The ANBU Commander would train him rigorously, so Naruto could be a prodigy in various ninja arts. His fighting style might be more calculated and less reliant on brute force and the Nine - Tails' power. He would have a better understanding of strategy and tactics.
In this fanfic, Naruto's relationship with the other villagers might be quite different. Since he is raised by the ANBU Commander, he may be more isolated from the general populace at first. However, as he grows, his skills and the influence of the ANBU could lead to him being respected in a different way. Maybe he would form a special team within the ANBU itself rather than the normal genin teams.
He would probably become more reserved. Naruto is usually very open, but as an ANBU commander, he'd have to keep secrets. So he might not be as quick to show his emotions.
He would likely become more secretive. Since ANBU operates in the shadows, Naruto would have to keep a lot of things to himself, which is a big change from his usually open - minded self. Also, the death of Asuma could make him more ruthless in combat, as he realizes the harsh reality of the ninja world. He may still hold onto his core values of protecting his friends and the village, but his methods could be more extreme in the ANBU.
Naruto's leadership style is all about friendship and believing in people. So, in the Anbu, he would likely encourage the members to trust each other more. He'd break down the cold and aloof image that the Anbu often has. Instead of just following orders blindly, Naruto would want his team to think for themselves and contribute ideas.
One possible scenario in such a fanfiction could be Naruto using his new godlike powers to reform the Anbu. He might introduce new training methods that are more humane yet highly effective, changing the often dark and secretive reputation of the Anbu. For example, instead of the traditional harsh and solitary training, he could promote team - based training where members learn to trust and rely on each other more.
Naruto may become more serious and stealthy. ANBU work requires a certain level of secrecy and discipline, which could tone down his usual exuberant personality.
He'd be more cynical. Orochimaru's ways would make Naruto question the goodness in people.
Naruto's character would likely become more reserved and stealthy. He'd be used to operating in the shadows, which is a big change from his normally boisterous self. His sense of justice might also be refined, as the ANBU has a different view on protecting the village.
One possible scenario in such a fanfiction could be that the Anbu Commander travels back in time to prevent a major tragedy in the Naruto world. Maybe he goes back to stop the Uchiha massacre. He could use his knowledge of future events and his Anbu skills to change the course of history.
Kakashi could be a great main character as an ANBU commander. He has the skills, experience, and the mysterious allure that suits the role. He's known for his combat prowess and his ability to think on his feet, which are essential for an ANBU commander.