Well, the plot could be that Naruto is the sole survivor after some kind of apocalyptic event. Maybe all the other shinobi were wiped out by a powerful enemy or a deadly disease. Naruto then has to find a way to rebuild the world while also dealing with his loneliness and the memories of his lost friends.
It could involve the last man's struggle to survive in a desolate world while also dealing with his own loneliness. Maybe he discovers a strange lemon - like plant that has some sort of special property that helps him in his survival. For example, it could provide him with a new source of energy or have healing abilities.
The plot could involve Jimmy exploring the now - empty world. He could discover some mysterious force that made everyone disappear. He then tries to reverse it. Along the way, he might have to deal with his own emotions as he misses his friends and family. He could also find some strange creatures or phenomena that he has to understand and overcome using his scientific knowledge.
In this fanfiction, Harry could be the last man on earth due to a powerful curse from an ancient dark wizard. He'd have to rely on his knowledge and skills that he learned at Hogwarts. He might try to communicate with the portraits in Hogwarts, hoping they can offer some guidance. As he delves deeper into the mystery, he discovers that there are some magical creatures that are also affected by this, and he has to find a way to save them all as well.
Another possibility is that Naruto himself could be his own antagonist in a sense. His loneliness and the weight of being the last man on earth could drive him to the brink of madness. He might have to fight his own inner demons, which could be manifested as a dark version of himself that wants to give up on the world and just let it decay.
Well, it could be about survival. Maybe he has to find food and water all by himself. He might also face threats from nature like wild animals or natural disasters.
Well, it could be about a man trying to survive in a post - apocalyptic world all alone. Maybe he's searching for other survivors while facing challenges like finding food and shelter.
It could be an ordinary guy. Just an average person who happened to survive whatever catastrophe wiped out the rest of humanity.
The plot could involve Naruto's journey to understand why he is the last male. He might search for answers across different lands. He could also encounter various challenges related to survival, as without other males, many aspects of society would collapse. He may have to take on roles that were previously divided among many. For example, he might have to learn all the skills necessary for maintaining a community, from farming to building shelters. Along the way, he could also discover some long - lost secrets about his own powers or the world that could help him either reverse the situation or adapt to it.
In this fanfiction, Naruto might feel extremely lonely at first. He would have no one to share his ninja dreams or have friendly competitions with. He might spend his days exploring the now-empty villages, reminiscing about the old times with his friends and comrades.
In a 'last human on earth fanfiction', the plot might center around the last human's attempt to preserve human knowledge. They could go to libraries and museums, collecting important books, artworks, and scientific findings. This would be a way for them to feel like they are still part of a greater human civilization, even if they are alone. And they may face challenges like natural disasters that threaten to destroy these remnants of humanity.