This type of fanfiction is likely to be very controversial. Naruto is known for his strong moral compass and love for his family. But in this scenario, if it's in a fan - made story, the writer might be trying to explore the boundaries of the Naruto universe. It could start with some event that drives Naruto to madness, like a false belief that Kushina was responsible for some great tragedy. Then, the story would have to deal with the consequences of such an unthinkable act, and how the other characters in the Naruto world would react to it.
In fanfiction, the idea of Naruto attacking Kushina is very uncharacteristic as they are mother - son. It could be a very dark or alternate universe scenario. Maybe in a plot where Naruto is mind - controlled or in a completely warped reality where family bonds are reversed.
Naruto would likely be deeply hurt, not just physically but also emotionally. He has always idolized his mother, so an attack from her would be a huge blow to his psyche. His trust in family and those close to him could be severely damaged.
Perhaps there's a time - travel element involved. Naruto from the future, who has been through some horrible experiences, travels back in time and, in a state of confusion or rage, attacks Kushina. Or it could be that a powerful villain has the ability to manipulate Naruto's emotions and uses that power to make him turn on his mother. This would create a very complex and dark plotline that challenges the normal Naruto narrative.
In some fanfictions, it might be due to an alternate timeline or reality. A change in the past could lead to Kushina having different beliefs or loyalties. It could also be related to a new power or curse that affects her judgment and causes her to see Naruto as an enemy. However, this is often a very dark and dramatic turn in fanfiction stories.
One possible reason could be mind control. Maybe an enemy of the village found a way to manipulate Kushina's mind and make her turn against her own baby. Another reason might be a misunderstanding. For example, she could have been tricked into believing that Naruto was a threat to the village in some way.
Maybe the village elders would get involved. They might try to figure out what went wrong with Kushina and at the same time, find a way to protect Naruto. Naruto could grow up with a lot of suspicion and fear from the villagers because of this incident, which would shape his character in a different way than in the original story.
Another aspect could be that the fanfiction delves into how Kushina's presence affects Naruto's relationships with others. For instance, his relationship with Sasuke could be different. With a strong maternal figure in his life, Naruto might be more stable emotionally and be able to approach Sasuke in a more understanding way, which could potentially change the whole dynamic of their rivalry and friendship.
In some fanfictions, the authors might take creative liberties and create alternate universes where Naruto and Kushina interact in different scenarios. For example, they could be on a joint mission together, and through that, we see their personalities shine. Kushina's fiery nature and Naruto's determination would make for an interesting dynamic.
One possible fanfiction could be about Kushina finding Naruto in a situation where he's lost in a forest. Maybe she uses her unique chakra sensing abilities to track him down. It could be a heartwarming story of a mother reuniting with her son.
In certain fanfic concepts, Naruto could have found a special relic or artifact. This relic might have the power to reverse death. Since Naruto is always on adventures and exploring different places, he might stumble upon such an item and use it to revive Kushina. It could also be related to the Uzumaki clan's secrets that he uncovers which enables him to bring his mother back.
Minato could be a common character. Since he was Kushina's husband in the original story, his presence might add some interesting dynamics to the harem scenario. Another could be Jiraiya. His connection to Naruto and his reputation as a bit of a ladies' man could make for an interesting addition to the story.