It could be a regular person, like a construction worker. They are used to dealing with tough situations and using their hands to fix things. In the 'last human on earth' scenario, they could use their skills to build a safe haven for themselves, fortify buildings against threats, and find creative ways to get resources. For example, they might know how to set up a water - collecting system from the rain.
It could be an ordinary guy. Just an average Joe who happened to be the one left. Maybe he was a simple office worker before the world changed.
It could be a young and brave girl, maybe a teenager who has been through a lot already in her life.
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.
A young child could be the last human alive. This would add a layer of innocence and naivete to the story. The child might not fully understand what has happened and is just trying to get by, relying on their instincts. They could be befriending animals or finding solace in nature, while at the same time being in great danger because of their lack of experience.
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.
Maybe a kind-hearted storyteller. They have the ability to communicate with the animals in the Lion King world through their stories. The animals are fascinated by the human's tales and the storyteller uses this to bring peace and unity among different animal groups, especially during times of conflict. They could also use their stories to inspire Simba to be a better leader.
It could be an ordinary guy. Just an average person who happened to survive whatever catastrophe wiped out the rest of humanity.
It could be a simple village girl. She might be kind, with a love for nature, which catches Legolas' attention. Maybe she has a special talent like being able to communicate with animals, which is something Legolas admires.
There could be a non - human villain like a powerful and corrupted magical creature. It might have been awakened by the chaos in the wizarding world and decided to wipe out all the wizards except Harry, seeing him as a worthy opponent or a key to some greater power it desires.
An orphan with special abilities could be the main character. They have no family or home, so when they land on Yautja Prime, they see it as a new start. Their special abilities, like being able to communicate with animals, might give them an edge in dealing with the native creatures of the planet and also intrigue the Yautja.