Perhaps it's a shinobi who has retired after a long and eventful career. He could be someone who has seen the darker side of the shinobi world and wants to make sure Naruto doesn't go down the wrong path. He might have been a wandering shinobi who finally settles down with Naruto. For example, he could be a shinobi from a different village who has a unique set of skills to teach Naruto.
Rebuilding and reform are also common. Naruto has always been about change and growth. So in his retirement, fanfics often show him using his influence to make changes in the village, like improving the education system or the living conditions of the villagers.
Obviously, Naruto is one of the main characters since it's about his retired life as a shinobi. Sakura could also be a main character, perhaps she still works as a medical ninja and has a different relationship with Naruto now that he's retired. Another could be Boruto, Naruto's son, as he would be affected by his father's retired status.
One possible plot could be Naruto dealing with the boredom of retirement. He might try to find new hobbies like gardening in Konoha. Maybe he starts teaching some young ninja in an unofficial way, passing on his unique skills and experiences.
One interesting plotline could be Naruto adjusting to civilian life after retiring. He might struggle with the boredom of not having the constant action and purpose he had as a shinobi. Another could be him mentoring the next generation in a more laid - back way, passing on his wisdom without the pressure of active duty.
One popular 'naruto retired fanfic' could be 'Naruto's New Beginnings'. In this fanfic, Naruto, after retiring from his shinobi duties, focuses on rebuilding the village in a different way, like through educational reforms. It shows a more mature and strategic Naruto, which is quite interesting.
Well, perhaps the retired shinobi has some secrets from his past. When he adopts Naruto, he starts to pass on these hidden techniques and knowledge. Along the way, Naruto might also help the retired shinobi come to terms with his own past traumas or unfulfilled dreams. As a result, they both grow and Naruto becomes a more well - rounded shinobi under this new mentorship.
Perhaps an old organization that was thought to be defeated resurfaces. They were biding their time while Naruto was hokage, and now that he's retired, they believe they can carry out their evil plans. They could be a group with a long - standing vendetta against Konoha and Naruto specifically. They might have new members or new powers that Naruto and his friends have to figure out how to counter.
One interesting 'Naruto retired' fanfiction could be about Naruto starting a new life as a simple farmer in the outskirts of Konoha. He uses his skills in a different way, like using his chakra control to help grow better crops. Another might focus on him mentoring the next generation in a more laid - back manner, away from the front - line battles.
One interesting 'Naruto Retired Ninja' fanfiction could be about Naruto starting a new life as a simple farmer, using his ninja skills in unexpected ways like creating efficient irrigation systems with his chakra control. Another might focus on him mentoring the next generation of ninjas in a more laid - back way, passing on his wisdom without the pressure of active duty.