The relationships in the fanfiction would be different. Naruto's friends and allies might react in various ways to his act of killing Kakuza. Some might support him if Kakuza was truly evil, but others might be shocked and question Naruto's actions. This is different from the original where Naruto's actions usually get a more unified positive response from his comrades.
Well, in the original storyline, there might not be a character named Kakuza at all. So right off the bat, this is a new addition. If Naruto kills Kakuza in the fanfiction, it would show a darker side of Naruto perhaps. In the original, Naruto is always about redemption and saving his enemies. But here, if he kills, it's a deviation from his usual character trait.
One possible motive could be that Kakuza has committed some heinous crimes against the Hidden Leaf Village. Maybe he has been involved in secret attacks on the village or has been plotting something really bad that would endanger the lives of many villagers. Naruto, being the protector of the village, would then take it upon himself to stop Kakuza by any means necessary, which unfortunately might end up in killing him.
In the original storyline, Yagura was the Fourth Mizukage who was being controlled by Obito. He was more of a victim. But in this fanfiction, Naruto kills him, which is a huge deviation as Naruto is usually about saving people. In the original, Naruto tries to understand and redeem his enemies, not kill them outright.
Well, in the original Naruto storyline, Minato is Naruto's father and he sacrificed himself to save the village and Naruto. So, in the fanfiction where Minato kills Naruto, it completely goes against this fundamental relationship. It changes the very essence of Minato's character from a self - sacrificing hero to a killer.
In the original, Naruto is the protagonist who is on a journey to become Hokage and gain the respect of the village. If Kushina kills Naruto in the fanfic, then all the dreams and hopes associated with Naruto are shattered. The whole narrative arc of the series is disrupted, and it could lead to a much darker and more despair - filled story for the other characters in the Naruto universe.
A significant difference would be the power dynamics. In the original, Naruto gains power through his own hard work, training, and the power of the Nine - Tails. In a fanfiction where he marries Kushina, there could be new power - sharing elements. Maybe they combine their Uzumaki chakra in unique ways. Also, the social aspect is different. In the original, Naruto is seen as an orphan trying to find his place. Here, he is part of a powerful couple. This changes how the other characters interact with him and how the story progresses in terms of village politics and alliances.
The original Naruto is about growth, friendship, and heroism. Naruto is depicted as a heroic figure who would never harm his family. In this fanfiction, the concept of Naruto as a 'god' and his act of killing his family introduce a very dark and uncharacteristic element. It changes the entire tone of the Naruto world from one of hope and perseverance to a much darker, more tragic one.
In the original Naruto story, Naruto is mainly focused on becoming Hokage and bringing peace to the village. However, in a 'Naruto is a Uchiha death fanfiction', Naruto's character arc might revolve around the Uchiha deaths. For instance, he could be more involved in uncovering the truth behind the Uchiha massacre or trying to prevent further Uchiha deaths.
The original Naruto plot focuses a lot on Naruto's growth within the framework of the ninja villages and his relationships with his friends and mentors. In a fanfiction with Shinju and Kaguya, the scope would be much larger. Naruto could be on a journey that takes him across different dimensions or time periods related to the Shinju and Kaguya. The fanfiction could also introduce new characters or races that are related to the Shinju or were once under Kaguya's rule. This would completely change the feel of the story, making it more of an epic adventure on a cosmic scale rather than just a story about a ninja's growth in a village.
Well, in the original storyline, Naruto is a very resilient character. He faces numerous challenges during the Chunin Exams but never gives up. He always tries to find a way forward. In this fanfic, the very act of Naruto killing himself is a huge deviation as it goes against his core character trait of perseverance.
The relationships within the Konoha ninja group would be different. Naruto's decision to give up on Sasuke might cause a rift among his friends. Some might support him, while others might think he's made a huge mistake. This would create new sub - plots and character developments that are not in the original story.