At first, Naruto would likely be very confused and hurt. He has always craved family love and acceptance, so this sudden turn would be a huge blow. He might try to plead with his family, asking them to believe him and give him a chance to explain.
His family would probably be overjoyed. After all, they might have thought they'd lost him forever. There would be hugs and tears, and a flood of questions about his life and what he's been through.
Shikamaru, being the laid - back yet perceptive friend, would probably think that Naruto has a plan. He would be concerned but also understand that Naruto is not one to make hasty decisions without a good reason. He might keep an eye on Naruto's family in his absence and hope that Naruto will return safely one day.
Well, in fanfiction, his classmates' reactions can vary widely. There are those who are his friends and they would be supportive. They might cover for him when he has to run off to be Spider - Man. On the other hand, there could be classmates who are envious. They might spread rumors about him or try to expose his secrets just out of spite or envy. And then there are the classmates who are just indifferent. They don't really care about Peter's secret life and just see him as an ordinary classmate most of the time.
A simple Nezuko and Zenitsu fanfiction could be that they go on a journey together. Along the way, they encounter other demon slayers who are initially skeptical of Nezuko. But Zenitsu stands up for her, explaining that she's different. This shows the depth of their friendship and how Zenitsu has come to trust Nezuko completely.