In the 'kushina kills naruto fanfiction', perhaps there's a misunderstanding that leads to this extreme situation. For example, Naruto could be framed for something really bad, and Kushina, believing the false information, takes drastic action. It's a really twisted concept compared to the original story where family is so important.
It's possible that in this fanfiction, the story is set in a world where the normal values of the Naruto world are inverted. Kushina might be under the influence of an evil force that wants to destroy Naruto as he is seen as a symbol of hope. This would completely change the dynamic of the Naruto story and lead to a very different kind of narrative.
There might be a very dark and twisted fanfiction like that. It could be that Naruto is tricked into believing that Minato and Kushina are some kind of threat to the village or to his friends. So in a moment of confusion and misinformation, he takes drastic action. But this goes completely against Naruto's character in the original series.
In such a fanfiction, perhaps Kawaki is driven by some extreme ideology. Maybe he believes Naruto's way of peace is a weakness and decides to take him out to change the ninja world in a more radical way.
Maybe the plot involves a mission where Naruto is sent to a realm that has been invaded by goblins. The goblins have a powerful magic item that they are using to gain an upper hand. Naruto has to fight his way through hordes of goblins, using his various jutsus like the fireball jutsu to clear paths. Along the way, he discovers the goblins' weakness and finally manages to kill the main goblin force, saving the day in this strange new world.
In a 'Naruto kills Gato' fanfiction, the plot could start with Gato's continued oppression in the Land of Waves. Naruto, having witnessed the suffering of the villagers, decides he's had enough. He uses his Shadow Clone Jutsu to surround Gato and his men. With a swift combination of Rasengan and his ninja skills, he takes Gato by surprise and defeats him, thus liberating the Land of Waves in a more direct and violent way compared to the original story.
One possible plot could be that Zeus somehow gets involved in the Naruto universe and starts causing chaos. Naruto, being the hero, decides to take him on. He could use his shadow clone jutsu to confuse Zeus and then land a powerful Rasengan on him. Maybe Zeus underestimates Naruto's abilities and is caught off guard, leading to his defeat.
The plot could involve Kakuzu being controlled by a more powerful and evil force. Naruto, after trying to reason with him and failing, has no choice but to kill him. This could also be a part of Naruto's growth, where he realizes that sometimes, in the face of extreme evil, killing is the only option to protect others.
Maybe a dark force takes over Naruto's mind. This force could be an ancient evil that has been sealed away for centuries and now wants to create chaos in the ninja world. It uses Naruto as a puppet to kill Tsunade, one of the most powerful protectors of the village. The story could then focus on Naruto's friends trying to free him from this control and avenge Tsunade.
One possible plot could be that they have to face challenges together in a post - war Konoha. They might work on rebuilding the village while also dealing with their new family life. Naruto, with his experience and Kushina's strong will, could make a great team in leading the village in a new direction.
In this fanfiction, the plot might involve Kushina coming back to help Naruto in his toughest battles. Maybe she uses her unique chakra abilities that Naruto has inherited to give him an edge. She could also provide emotional support, as Naruto has always longed for his mother.
One possible plot could be that Naruto somehow inherits the Rinnegan from an unexpected source and Kushina, being his mother, helps him understand and control this new power. Maybe they discover a hidden connection between the Uzumaki clan and the Rinnegan's origin, leading them on a journey to uncover secrets long lost in the ninja world.