Well, it could be that Naruto sacrifices himself to seal away a dark and ancient curse that is threatening to destroy not only the ninja world but all of existence. He realizes that his unique connection to the tailed beasts and his strong willpower make him the only one who can perform this self - sacrificing sealing jutsu. So, he says his goodbyes to his friends, family, and the village he loves and gives up his life to save everyone.
It could be a long - lost Uchiha with powers beyond that of Madara. This Uchiha could have been in hiding, gathering power and knowledge, and his ultimate goal is to reshape the world in his own dark image. Naruto realizes that the only way to stop him is by sacrificing himself.
In fanfiction, Naruto sacrificing himself for Obito could be a very emotional and dramatic concept. It might show Naruto's ultimate selflessness, believing that Obito is worth saving at the cost of his own life. This could be due to Naruto seeing the good in Obito that others might not, like the part of Obito that was once a kind - hearted shinobi.
Perhaps in the fanfiction, Naruto gives his life energy to Boruto to save him from a deadly curse. Boruto then has to deal with the newfound power within him, which is a mix of his own and his father's. He may struggle to control it at first but eventually learns to use it for good. This could also lead to a rift between Boruto and some of the villagers who blame him for Naruto's death.
In such a fanfiction, the plot could involve Naruto sacrificing himself to save the Hidden Leaf Village from a powerful and seemingly unstoppable enemy. Maybe it's a new, more menacing form of the Akatsuki that has emerged with a doomsday - like jutsu. Naruto, being the hero he is, decides that the only way to protect his friends and the village is by using a self - destructive jutsu that nullifies the enemy's power but at the cost of his own life. His sacrifice could lead to a period of mourning in the village, with his friends like Sasuke feeling guilty for not being there to prevent it and vowing to carry on Naruto's legacy of peace.
One possible plot could be that in a final battle against an extremely powerful enemy, Naruto realizes that the only way to save Hinata and the entire village is by using a forbidden jutsu that will cost him his life. He makes this sacrifice with a smile on his face, knowing that Hinata and the others will be safe. Hinata is heartbroken but also determined to carry on Naruto's legacy of protecting the village.
I'm sorry I can't directly recommend a specific 'Percy sacrifices himself for Artemis' fanfic. But you can try searching on fanfic platforms like Archive of Our Own (AO3). There are tons of fanfics there, and by using relevant keywords in the search bar, you might be able to find one that suits your interest.
In the fanfic, it could be that Fleur is in a situation where she has to perform a dangerous task to save the wizarding world, like going into an ancient and deadly magical place. Harry, realizing the importance of her mission and also having deep feelings for her (maybe a secret love), sacrifices his own safety by going with her and ultimately giving his life to ensure she can complete the task and save everyone.
Well, the Kyuubi itself would probably be changed. Naruto had a deep bond with it. His sacrifice might make the Kyuubi more empathetic towards humans. It could even decide to protect the village in Naruto's memory. On the other hand, the next generation of ninja would grow up without Naruto as their inspiration. They would have to find new heroes to look up to, and the stories of Naruto's deeds would become more like legends, with a bittersweet feeling of what could have been if he had lived.
One possible consequence could be that Konoha would enter a period of deep mourning. Naruto is a beloved figure, and his sacrifice would leave a huge void. The villagers might be inspired by his selfless act to strive for a more peaceful and united Konoha. His friends, like Sasuke, might be filled with a new sense of purpose, perhaps to carry on Naruto's ideals in a more aggressive way to ensure his sacrifice wasn't in vain.