In fanfiction, the reanimation jutsu might have extended or modified limitations. For instance, in the original, there were clear rules about the caster's control over the reanimated. But in fanfiction, a writer could create a scenario where the reanimated can break free of that control more easily. Also, the source of the sacrifice for the jutsu could be different. In the series, it was usually human sacrifices, but fanfiction might explore using other forms of energy or substances.
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.
One interesting idea could be the reanimation of minor characters from the Naruto series and exploring their backstories that were not fully told in the original. For example, reanimating a random shinobi from a minor clan and showing how their clan's unique abilities could have been used more effectively in the war. Another idea might be the reanimation of characters from different time periods in the Naruto universe's history, like shinobi from the era before the Hidden Villages were established.
Naruto's character would experience significant growth. The reanimation jutsu is a very powerful and morally ambiguous technique. Naruto, who is known for his positive attitude and strong moral compass, would have to figure out how to use it in a way that aligns with his values. He might start to question some of the long - held beliefs in his ninja world. For instance, he might wonder if bringing back the dead is really that bad if it can be used for a greater good. This internal struggle would shape him into a more mature and nuanced character. He would also have to deal with the reactions of his comrades, which could range from admiration to fear, and this would further impact his development.
Some fanfictions might depict Naruto as having a deeper understanding of the chakra system than ever before. He could have found a way to disrupt Madara's connection to the chakra source, or maybe he was able to use his own chakra in a way that nullified Madara's powerful jutsus. Also, Naruto's experience from all his previous battles might have led him to anticipate Madara's moves and strategies, allowing him to stay one step ahead and ultimately defeat him.
Maybe he found some hidden scrolls left by his mother. These scrolls could have contained the details of her jutsu. Naruto, being the curious and determined ninja he is, would have studied these scrolls carefully and learned the jutsu.
One common theme is redemption. The reanimated characters often get a chance to right their past wrongs. Another is the exploration of old relationships. Since they come back, they can re - interact with their former friends or foes.