In a Naruto dying of sickness fanfiction, you could explore the impact on the village. The villagers who once shunned him now feel a sense of loss. They start to realize how much he has done for them. For the actual writing of his sickness, make it a slow - burning process. He first gets tired easily, then has fainting spells. His friends try everything to save him, from searching for rare herbs to trying experimental jutsus, but in the end, he succumbs to the illness, leaving behind a legacy.
Definitely when Naruto can no longer perform his signature Rasengan. He tries so hard but his body just won't allow it. His friends are there, watching helplessly. Also, the moment when he has a final conversation with Iruka - sensei, reminiscing about the old days when Iruka was the first to believe in him. It's a connection to his past that is being severed by the illness, which is very poignant.
Show Naruto's fear and regret. For example, he might regret not spending more time with his family or not achieving all his goals for the village. His fear of leaving his loved ones behind, especially his children, can be a very emotional aspect.
In a fanfiction of Naruto dying of a sickness, perhaps the sickness is a result of overusing his chakra during a great battle. His body starts to break down, and he begins to experience weakness and fainting spells. Hinata, being his wife, is desperate to find a way to save him. She might turn to her own clan's secrets in hopes of finding a cure. At the same time, Naruto tries to train Boruto in what little time he has left, passing on his values and skills, while also coming to terms with the fact that he won't be there to see his son grow up fully.
In some fanfictions, the cause could be a curse. There could be an old enemy of the village or someone with a vendetta against Naruto who placed a curse on him. This curse could be slowly draining his life force, causing him to become sick. Or, it could be related to the tailed beast inside him. Maybe there was some imbalance in the chakra of the Nine - Tails that was affecting Naruto's health. It's also possible that he caught a strange and rare disease from an unknown source during one of his travels to a far - off land.
I'm not entirely sure if there is a specific 'Naruto Sings Time of Dying' fanfiction. Fanfictions cover a wide range of scenarios and ideas. It could be that such a unique concept exists, but it might also be a very niche or even new idea that hasn't been written yet. You could also try reaching out to Naruto fan communities on social media platforms to ask if anyone has come across such a fanfiction.
Well, Naruto's chakra control would have to adapt. In the Dying Light world, he might use his chakra to enhance his weapons, like making a kunai cut through the tough zombie hides more easily. His Rasengan could also be modified. Instead of just being a powerful close - range attack, he could potentially throw it like a grenade in the Dying Light environment, causing a lot of damage to groups of zombies. And his sensing ability, which he uses to detect enemies in his own world, could be used to sense the approaching zombie hordes from a distance.
One possibility could be that Naruto has been poisoned by a new and unknown enemy. This poison is slowly eating away at his life force, and he's trying to hide it from his friends and family so as not to worry them. He might be secretly seeking a cure while still fulfilling his duties as Hokage.
It could be a rogue shinobi from Naruto's past who has been biding his time. This shinobi might have developed a new jutsu specifically designed to target Naruto and make him die slowly. He's doing it secretly to cause chaos in the Hidden Leaf when their hero suddenly passes away.
The people closest to Naruto, like Hinata, would be completely devastated. She would be by his side, crying and feeling like her world is falling apart. The thought of losing Naruto, the man she loves, would be almost too much to bear.