It could also be that they are inexperienced writers who don't fully understand Naruto's character. They might not have grasped the core values of the Naruto series, like friendship, hard work and perseverance, and instead create a very out - of - place version of Naruto who likes to kill just to create a different kind of plot.
One reason could be to explore a unique power combination. Naruto is known for his own powerful jutsu like the Rasengan, and combining it with the Susanoo, which is a very powerful Uchiha ability, makes for an exciting and fresh concept in the Naruto universe.
One reason could be to explore alternative storylines. The original 'Harry Potter' series has a set path for the relationships, but fanfiction writers like to break the mold. Maybe they think Hermione and Ron's brother could have an interesting dynamic that wasn't explored in the books. Another reason could be to add more drama. A relationship like this would surely cause a stir among the characters in the wizarding world, and it makes for an exciting plot.
Maybe to focus on other aspects of Naruto's character like his determination. Without love in the story, it can show his single - minded pursuit of being a great ninja.
Some writers might write it to explore the darker side of characters. They want to see how a usually positive character like Rias can turn bad and how Naruto would react in such a situation. It's all about exploring different character dynamics.
It could be a creative exercise in exploring how a single event, like Kushina killing Naruto, would change the entire Naruto universe. Writers might be interested in seeing how other characters would react, how the story would progress without Naruto, and how the themes of the original story would be altered. For instance, the theme of friendship and mentorship would be severely affected. It's also possible that the writer wants to shock the readers and make them think about the characters in a completely new light.
Maybe for shock value. By having characters cheat, it can create a big stir in the story. It grabs the reader's attention because it goes against what we expect from the usually honorable Naruto characters.
It could be that a very small number of individuals with warped ideas are attracted to creating such disturbing content. However, they are not in line with the general values of the Naruto community. The Naruto series is about so many positive things like ninjutsu, comradeship, and protecting the village. This kind of inappropriate fanfiction is a deviation from those positive themes.
One reason could be to explore alternative scenarios. They might think 'what if Naruto had this super - broken power?' and write a fanfic around it. Also, it could be a way to stand out. In a sea of Naruto fanfics, having a really out - there concept like a 'broken' Naruto might attract more readers.
It could be that they have a very different interpretation of Naruto's character. However, this is a very extreme and negative way of expressing that view. They might not understand or appreciate the values and growth that Naruto represents in the original story, and instead choose to write something so unkind.
There are several motives. Firstly, it could be a form of wish - fulfillment for the writer. They might have always thought about what would happen if Ash was experimented on and decided to put it into a story. Secondly, it can be a means of world - building. If the fanfiction has a different world or setting, experimenting on Ash could be a way to show the rules and capabilities of that world. For example, if it's a dystopian world, the experiment on Ash could highlight the cruel and unethical practices of that society. Also, it might be to create a contrast. If Ash is usually seen as a strong and in - control character, the experiment can break that image and show a more vulnerable side, which can be really interesting to explore in a story.