Naruto being in the Bingo Book means his freedom is restricted. He can't move around as freely as before. He has to be cautious of every new face he meets because anyone could be a bounty hunter. Also, his relationships with the villages might become strained as they are now hunting him, even if he is innocent.
When Naruto is in the Bingo Book in fanfiction, his entire world is turned upside down. His reputation takes a huge hit. People who once respected him might now see him as a criminal. His access to resources and support from the ninja villages is cut off. He has to find new ways to survive, like relying on his own skills and the loyalty of a few close friends. He also has to be strategic about where he goes and what he does to avoid being caught, which is a big change from his normal, more open - ended adventures.
His confidence might increase. Knowing that he's considered a threat in the Bingo Book could make Naruto feel more powerful. He might start to believe more in his own abilities and be more assertive in battles.
Naruto's personality might show a more serious side. Wearing a suit could make him feel more responsible, like he has to represent the Hidden Leaf in a proper way. So he'd be less likely to crack jokes and more focused on the task at hand.
Naruto might become more calculating. Since Mewtwo is very intelligent and has powerful psychic abilities, Naruto would have to use his mind more. He would think before acting, unlike his impulsive self in the original series. This change could make him a better strategist in battles, but it could also lead to misunderstandings with his friends who are used to his more straightforward and impulsive nature.
His life changes drastically. Firstly, his social status within the village would be very different. People might fear him initially. His relationships with friends like Sasuke and Sakura would also be affected. They would have to adapt to this new Naruto. His training regime would change completely as he has to learn to control his new bijuu form. He might have to isolate himself at times to avoid causing harm.
He becomes more aggressive. His friendly nature is gone and he's quick to lash out.
Naruto's personality could shift towards being more reserved. As a Shinigami, he has to deal with the weight of handling souls and the concept of death. This could make him think twice before acting impulsively like he used to. He may also develop a more empathetic side towards those who are about to die or have lost loved ones, as he now has a closer connection to the afterlife.
Naruto's character would change in several ways. Firstly, he would become more strategic. As a lord, he has to plan for the long - term development of his land, which requires thinking ahead. His impulsiveness would be curbed as he has to deal with the complex web of politics. He would also grow in terms of wisdom. He would learn from his experiences and the advice of his advisors. His charisma would be used in a different way. Instead of just inspiring his ninja comrades, he would need to inspire all his people. His sense of justice would expand from individual cases to the overall fairness of his domain, and he would strive to make his territory a model of a just society.
He becomes more serious. Gone is the Naruto who is always cracking jokes.
Well, he might start by reforming the bureaucracy. He'd probably use his experiences from Konoha to bring in more efficient systems. He could also focus on improving trade relations, given his wide network of friends from different villages. Naruto would likely try to make the decision - making process more inclusive, listening to the voices of the common people and the ninja clans alike.
His character might become more cautious. In the Naruto world, he's used to certain types of danger, but the real world has different and often more hidden threats. So he'll have to be more careful.