There's no way to know the author just from this title. Fanfiction is a vast world with countless creators. It could be a relatively unknown writer who just wanted to explore this unique and somewhat dark concept. Maybe it was written by someone who was experimenting with different ways to tell a story within the existing fictional universe related to Sakura.
In this kind of fanfiction, the death of Sakura in a wave might be used to create a sense of tragedy. It could be a way to explore themes like loss, the power of nature, or the fragility of life. For example, it might show how a character like Sakura, who could be seen as innocent or full of life, is suddenly taken away by the force of the wave, which can be a very powerful and emotional concept.
Since I don't know the specific fanfic, Sakura is likely one of the main characters as it's in the title. There may also be characters related to her, like her friends or family who are affected by her death in the wave.
I'm not sure specifically as there could be many different 'sakura dies in wave fanfic' out there. It might involve a story where a character named Sakura meets her end in a wave - related scenario, perhaps a tsunami or a powerful ocean wave in a fictional world.
Definitely Naruto. He's always been there for Sakura, no matter what. He would use his Nine - Tails chakra if he had to in order to save her. Sakura's female friends like Ino could also play a role in her rescue. Ino is a skilled ninja in her own right and has a deep friendship with Sakura. And don't forget Tsunade. As the Fifth Hokage and Sakura's mentor in the medical field, she would do everything she could to save Sakura's life.
I don't know who the author of 'the last wave novel' is. There are so many novels out there and this one might be by an emerging author or a relatively unknown one.
In addition to Sasuke, Kakashi, and Sakura, other characters like Iruka sensei would be affected. Iruka was one of the first people to believe in Naruto. Naruto's death would be a huge blow to him. Also, the villagers of Konoha who had started to see Naruto in a new light might have to re - evaluate their views. And characters in the Land of Waves, like Tazuna and his family, who had come to rely on Naruto's help, would also be impacted. They might lose hope or face greater danger without Naruto there to protect them.
In this kind of fanfiction, Sasuke could die from a sneak attack. He might be so focused on his main target during the Wave mission that he doesn't notice another hidden threat. And this hidden enemy could strike him when he least expects it, leading to his death. For example, an assassin could be hired to specifically target Sasuke and use some sort of poison or a deadly jutsu that he can't defend against in time.
Well, the entire Konoha village would likely mourn Sakura's death. She was a respected ninja, a medic - nin who had saved many lives. Her teammates, like Kakashi, would be deeply saddened. He had trained her and watched her grow. Also, all the young ninja who looked up to her as a role model would be heartbroken. Her death would be a huge blow to the village's morale.
I'm not sure specifically as there could be many different versions of such a fanfic. But generally, it might involve Naruto facing some overwhelming danger in the Wave arc that leads to his death, perhaps a more powerful enemy than in the original story or a failed mission that costs him his life.