It could be a way for the writer to explore a tragic or 'what - if' scenario. For example, if there was misinformation or a huge misunderstanding between Naruto and Neji. But still, it's a very unorthodox and shocking concept considering the original relationship between the two characters in the Naruto series.
One possible motive could be a dark or alternate universe take. Maybe in this fanfic's world, there is some sort of dark magic or mind control that forces Naruto to do it against his will.
One possible motive could be power. In some fanfics, Sasuke might be driven by an insatiable thirst for power and see Naruto as an obstacle. Another could be revenge, perhaps believing Naruto has wronged him in some way in that alternate story. Or it could be a matter of being corrupted by dark forces, which make him turn against Naruto.
One possible motive could be a dark magic or mind - control situation. Maybe an enemy has the power to control Naruto's actions and forces him to kill Sasuke against his will. Another could be a miscommunication where Naruto believes Sasuke has done something unforgivable, like harming the village in a way that Naruto can't overlook.
It could also be related to a prophecy or a pre - determined fate in the fanfic's plot. There might be some kind of dark prophecy that says Kawaki has to kill Naruto to prevent a greater evil. Or perhaps Kawaki is being controlled by an external force that has a vendetta against Naruto and uses Kawaki as a tool to carry out the murder.
Another motive might be related to some dark power corrupting Team 7. This power could have twisted their minds and made them see Kakashi as an obstacle in their path to achieving ultimate power. It could be something like the curse mark in the original Naruto series but even more powerful and insidious.
One possible motive could be a complete breakdown of the peace they had worked so hard to build. Maybe an outside force manipulates Gaara's mind, causing him to turn on Naruto. Another could be extreme jealousy over Naruto's popularity or power.
One possible plot could be that Hinata is somehow mind - controlled. Maybe an enemy uses a powerful genjutsu on her that makes her see Neji as a threat to Naruto or to the village. Under this influence, she attacks and kills Neji, which then leads to a great deal of guilt and self - loathing for Hinata once she breaks free from the control.
One possible motive could be Anakin's fall to the dark side. The dark side twists his perception and he might see Ahsoka as a threat to his newfound power or loyalty to the Sith. Maybe he believes she would try to stop him from achieving his dark goals.
One possible motive could be revenge. If Pauna had done something really bad to Clarke or someone Clarke cares about in the fanfic's backstory, Clarke might feel compelled to kill Pauna. Another could be self - defense. Maybe Pauna was attacking Clarke and she had no other choice.
Yes, there might be such a fanfiction. In the Naruto fandom, with its large and diverse range of fan - created works, various out - of - canon scenarios are explored. However, this goes against the original storyline where Hinata and Neji have a complex relationship that is more about growth, understanding, and family bonds rather than such a violent act.
It's a very controversial plot. Neji is an important character in Naruto, and his relationship with Naruto is complex but not one of enmity to that extreme. In the original story, they are comrades. So a fanfic with such a plot goes against the general spirit of the Naruto world and would shock many fans.