If Naruto becomes a Hunter Nin in fanfiction, his personality would change significantly. He'd be more calculating. His usual impulsive nature would have to be toned down because one wrong move as a Hunter Nin could mean disaster. He might also become more solitary, used to working alone in the shadows rather than in a team. His sense of humor might also be more subdued as he takes on this serious and dangerous role.
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.
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 personality would likely become more patient. As a medic nin, he would need to be calm and focused during treatments. His impulsiveness would probably decrease as he realizes that any hasty move could harm a patient. He might also become more empathetic, understanding the pain and suffering of others on a deeper level.
If Naruto becomes a hunter nin in the fanfic, his sense of justice could become more complex. As a hunter nin, he'd be exposed to different shades of right and wrong. He might not be as quick to judge someone as he used to be. Instead of simply seeing enemies as bad guys, he'd start to understand the reasons behind their actions. This could make him more empathetic but also more calculating in his approach to dealing with threats. Also, his normally boisterous nature would likely be toned down to avoid attracting unnecessary attention.
His personality might become more aggressive. The demon nature could bring out his primal instincts, making him less patient and more prone to anger.
He might become more serious. He realizes the weight of his responsibilities, so he's not as carefree as before. But he still tries to keep his positive and determined attitude.
He might become more cautious. As a bounty hunter, one wrong move could cost him his life. So, he would be less reckless than he was as a ninja in some battles. But his core of being kind and believing in second chances would still be there.
He might become more cunning. Just like a fox, he would be able to outwit his enemies more easily. He could use trickery and deception in battles, setting traps for his opponents.
He becomes more decisive. As a leader, Naruto can't afford to be indecisive like he sometimes was in his youth. He has to quickly make choices that affect the whole village or group he's leading.
He might become more patient. As a dad, he has to deal with his kids' tantrums and mistakes, so patience is key.