In a fanfiction where Naruto gains One for All, there are a lot of possibilities. One for All gives the user enhanced strength, speed, and durability. Naruto already has a great deal of experience in combat and a strong will. This new power would allow him to face stronger opponents with ease. For example, he could take on the Akatsuki members more easily. Also, the way he trains and how he passes on his knowledge to others might change. He could potentially teach his friends how to better utilize their own powers in relation to One for All's abilities. His relationship with Sasuke might also be affected as they would have to re - evaluate their power levels in comparison to each other.
Well, he'd probably become super powerful. The symbiote suit could enhance his physical abilities like speed, strength, and agility. He might also gain some new jutsu or combat techniques based on the nature of the symbiote. For example, if the symbiote has some sort of dark or shadow - like property, Naruto could incorporate that into his attacks, making them more unpredictable.
If Naruto gains the power of Beerus in fanfiction, he would become extremely powerful. His already impressive combat skills combined with Beerus' god - like power would make him nearly unbeatable. He could easily defeat the toughest of foes in the Naruto universe with a single blow.
If Naruto gains the abilities of Kratos in fanfiction, he would become extremely powerful. Naruto already has his own set of powerful jutsu, but with Kratos' abilities like superhuman strength, enhanced combat skills, and his rage - fueled power, Naruto could defeat almost any enemy with ease. He might be able to take on stronger foes like Kaguya even more effortlessly and protect the Hidden Leaf Village in a much more dominant way.
Well, Naruto would become extremely fast. He could zip around the battlefield in an instant, catching his enemies off - guard. His combat style would change drastically as he could now close the distance between him and his foes before they could even react.
Well, in the 'naruto gains kyuubi's powers fanfiction', Naruto might face new challenges as well as new opportunities. On one hand, he would be a target for those who fear his new - found power. On the other hand, he could use this power to protect his village better. He might also develop new techniques that are a combination of his own skills and the Kyuubi's power, like a new type of shadow clone jutsu infused with the Kyuubi's chakra.
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.
In a fanfiction where Percy gains all of Kronos' powers, he would likely become extremely powerful. He could have control over time, which is one of Kronos' major abilities. This might lead to him being able to manipulate events in ways no one else could. For example, he could go back in time to prevent disasters or change the outcome of battles.
He would probably start to see the world in a different way. Since Hephaestus skills involve a deep understanding of mechanics and construction, Percy might start noticing the weak points in buildings and how things are put together. This could be useful not only in battles but also in his daily adventures. He could use his newfound skills to repair things quickly or even modify existing structures to make them more defensible. Also, he could communicate better with the Hephaestus cabin kids, sharing ideas and learning from them about different crafting techniques.
Madara Uchiha could also be an antagonist in this scenario. Even if he's dead in the original story, in the fanfiction, his influence or some sort of resurrection could occur. He might view Naruto's immortality as a hindrance to his own plans for the ninja world or simply be jealous of Naruto having such a power that he never had.
With the Rinnegan, Naruto might gain the power of the Human Path. This would allow him to read minds or rip out souls, which is a very dark and powerful ability that would be quite different from his usual positive - natured powers.