Well, he could be made to do all sorts of things against his will. Maybe he'd be forced to fight his friends. It would be a really dark turn for his character, as Naruto is known for his strong will and loyalty.
In some fanfictions, the brainwashing jutsu on Naruto could be part of a bigger scheme. For example, a new villainous organization wants to use Naruto as a weapon. They brainwash him and try to control his immense power. But Naruto's willpower, even under the jutsu, might start to show through in small ways, and his friends use these glimmers to figure out how to save him.
Another possibility is a new, unknown enemy. This could be someone from a far - off land who has heard of Naruto's power and developed a special brainwashing jutsu just to take over Naruto and use him to conquer other villages.
Well, he could become extremely powerful. Maybe he'd use the forbidden jutsu to defeat powerful enemies like Madara or Kaguya in a really unexpected way. For example, if it was a time - travel related jutsu, he could go back in time and stop certain events from happening that led to the rise of these villains in the first place.
Perhaps with the help of his strong bonds with his friends. Their love and trust could be the key to snapping him out of it.
Well, it would be really strange. Naruto is from a world of ninjas with their own set of rules and weapons like kunai and shuriken. If he got a gun, he might be able to defeat his enemies more easily in a way that goes against the traditional ninja battles. But he would also have to learn how to use it properly, and it could change the whole dynamic of his relationships with his friends and enemies.
If Naruto gets the Byakugan in the fanfiction, it would be a game - changer. Firstly, his training would take a different turn as he'd need to master the Byakugan's capabilities. He could use it to predict his enemies' moves more accurately. In team battles, he'd be able to provide more detailed information about the enemy's positions and weaknesses. This new power could also make him a target for those who fear his growing strength, leading to new and exciting plot twists.
Well, he'd probably be super OP. He could transform into all kinds of alien forms and use their powers in his battles. Imagine Naruto using Heatblast's powers to fight against Akatsuki members. It would be a whole new level of combat in the Naruto universe.
Well, in fanfiction when Naruto gets shot, the story could take a really dark turn. His injury might incapacitate him for a while, leaving Konoha vulnerable. This could force his friends to step up and take on his responsibilities. Maybe Hinata would be by his side constantly, using her Byakugan to monitor his condition. And his sensei, Kakashi, might have to come up with a new strategy to deal with the situation while Naruto recovers.
Well, he'd probably be an even more powerful force. The Keyblade has its own unique powers and abilities. Naruto's already strong ninja skills combined with the Keyblade could make him nearly unbeatable. He might use it in combat in ways similar to how he uses his ninja tools, but with added magical elements. For example, he could use his chakra to enhance the Keyblade's attacks.
Well, in a fanfic where Naruto gets the reanimation jutsu, it would change a lot of things. Naruto is a character who values life highly. He might struggle with the moral implications of using such a jutsu. On one hand, it could be a great strategic advantage, but on the other, it goes against his principles. He might use it in a very different way than others, like only bringing back those who died unjustly to give them a chance to right the wrongs.