Perhaps he would change to Naruto Storm. 'Storm' can represent his powerful and sometimes tempestuous nature. In the series, Naruto has shown great strength and determination that could be likened to a storm, which is both destructive and at the same time a force of change.
It could also be due to a prophecy or some sort of spiritual guidance. In the Naruto universe, there are often prophecies that guide the characters' actions. A prophecy might suggest that changing his name would bring about some great change or power. For instance, if there was a prophecy that a new name would help him unlock a hidden power or unite different ninja clans under a new banner.
His character would become more secretive. Instead of being the open - hearted Naruto we know, he'd have to keep things to himself. For instance, he couldn't share all his thoughts and experiences with his friends right away.
His confidence could turn into over - confidence bordering on arrogance. As a villain, he might think he is above everyone else and that his way is the only right way. He would no longer listen to advice or consider the consequences of his actions on others, believing that he can handle any situation on his own, no matter how dangerous or unethical.
Clothing changes can also represent his emotional state. If he's wearing something more somber and dark, it might indicate a period of self - reflection or dealing with a difficult situation. For example, after a major battle where he loses a friend, he could change into all - black clothes as a sign of mourning.
Maybe a plot where Naruto's change in gender affects his relationships. His friends like Sasuke and Sakura might react in different ways. Sasuke could be more protective, or Sakura might see her as a new kind of rival or friend. Also, Naruto's relationship with his mentor Kakashi could change as Kakashi has to adapt to training a female ninja with Naruto's unique abilities.
Well, Naruto's personality could become more empathetic. In the male form, he was often brash and focused on his own goals. But as a girl, she might start to see things from other people's perspectives more easily. Maybe she'll be more in tune with the emotional needs of her friends and comrades, and this could change the dynamics of her relationships. Also, she might become more nurturing, which is a trait often associated with female characters in the Naruto universe.
Sasuke might be initially suspicious. Given their complex relationship, Sasuke would likely want to know the real reason behind Naruto's identity change. But once he understands the motives, he might respect Naruto's decision if it's for a good cause.
With his friends, it could initially cause confusion. They are so used to calling him Harry that the new name might be a bit of a shock. But if they understand his reasons, they would likely support him. For example, Hermione might be the first to adapt and help others adjust, using her logical thinking to see the benefits of the name change.
If Harry Potter changes his name to Wizard in fanfiction, it might symbolize a new beginning or a desire to break away from his past. It could also make for some really interesting plot twists. For example, his friends might not know it's him at first, and there could be a whole mystery around who this 'Wizard' really is. This could add an element of intrigue to the fanfiction.