If Naruto is kidnapped by Kumo in fanfiction, it could lead to a series of intense battles. Naruto himself might try to escape on his own using his ninja skills and the power of the Nine - Tails. His captors in Kumo would probably want to extract some sort of information from him, like the secrets of the Nine - Tails or Konoha's defense strategies. However, Naruto is a tough character and would surely put up a fight.
Naruto could try to befriend some of the Kumo ninjas who might not be in favor of the kidnapping. By winning them over, they could help him escape. Also, he could use his knowledge of ninja techniques and his quick thinking. For example, he could use substitution jutsu to switch places with an object when the guards are not looking and then make a run for it.
It could be that Kumo has a rogue group within their village that wants to use Naruto for their own malicious purposes. They kidnap him in the chaos of a diplomatic visit or something similar. Once kidnapped, Naruto finds himself in a difficult situation as he is far from home. But he uses his never - give - up attitude and starts making friends with some sympathetic Kumo ninjas who help him in his fight against the rogues and eventually his escape back to Konoha.
One way could be a stealth mission. Shikamaru, with his high intelligence, could plan a strategy to infiltrate Kumo's hideout undetected. He could gather a small team of skilled ninja like Neji (if he were still alive in the fanfiction), Rock Lee, and Ino for mind - reading and communication. Then they could free Naruto and Hinata and escape before Kumo realizes what's happening.
If Naruto and Hinata were kidnapped by Kumo in fanfiction, it could lead to a major diplomatic crisis between the Hidden Leaf and Kumo. Naruto, being the hero of the Hidden Leaf, his kidnapping would enrage the villagers. Hinata, as his wife, her kidnapping would add to the urgency. Kumo might have kidnapped them for Naruto's power or to use Hinata as a hostage to gain some sort of leverage over the Hidden Leaf. The Hidden Leaf would then have to figure out a way to rescue them without starting a full - scale war.
Naruto might become more cautious. After being kidnapped, he realizes the world is more dangerous than he thought. He could start to be less impulsive and think more before acting.
One possible plot development could be that Naruto's friends in Konoha realize he's missing and start a search mission. They might suspect Kumo immediately due to the history of tensions between the two villages. Meanwhile, in Kumo, Naruto could be held in a secret location. Some in Kumo might want to use him as a bargaining chip against Konoha, while others might see his potential and try to turn him into an asset for Kumo.
Definitely the Kumo ninjas who carry out the kidnapping. There could be some well - known Kumo characters like Killer Bee. He might be involved either directly in the kidnapping (unlikely as he is more of a good guy in the original) or in the events that follow. Another character could be the Raikage. He may or may not be aware of the kidnapping depending on the plot. If he is aware, his actions and decisions would play a major role in how the story unfolds.
Well, one potential partner could be Omoi. I know he's male, but in some fanfictions, gender - bending or same - sex relationships are explored. Omoi's unique personality, with his over - thinking and yet loyal nature, could create an interesting relationship with Naruto. However, if we stick to the more traditional female partners, Yugito Nii could also be a great choice. She was a jinchuriki, just like Naruto, and they could share a special bond based on that shared experience.
Naruto would probably use his friendly and outgoing nature to adapt. He'd start by getting to know the people around him, like his new family and the local ninjas. He might also be interested in Kumo's unique jutsu and training methods, which would help him fit in. And of course, he'd keep his goal of promoting peace between Konoha and Kumo in mind, which would give him the motivation to overcome any difficulties in adapting.